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Care and handling of "diesel lump"

MD5 for Dummies

Volvo Penta MD5 110S drive

Stefan Fors,
Västerås, Sweden
UPDATED November 15 2009

Picture 1.1, our own Volvo Penta MD5A. with modern 70 Ampere generator, picture year 2004.
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1. Introduction .............................................. ................................................... .............................. 4

1.1 Preface ................................................... ................................................... .............................................. 4

1.2 Principle of 4-stroke diesel ........................................... ................................................ ................... 7 1.3 General

description of the engine ......................... ................................................ .......................... 8 1.4 Description of how

the motor works ................. ................................................ ..................... 10

1.5 How to run the engine ............................................. ................................................... ....................... 12

1.6 Life expectancy .............................................. ................................................ ....................................... 12 1.7 What

you can do yourself on the engine .. ................................................ ....................................... 14 1.8 Pictures and

exploded views ...... ................................................ ................................................ .. 15

2. The fuel system .............................................. ................................................... .................... 27

2.1 General information on fuel systems .............................................. ................................................ ......... 27 2.2 Pre-

filter with water separator – Extra fuel filter ................................. ............................. 28 2.3 Fuel pump - feed

pump ................ ................................................ ....................................... 31

2.4 Fine filter - Fuel filter ............................................... ................................................... ................... 35

2.5 Venting the fuel system .............................................. ................................................... ...... 36 2.5.1 Description of the
ventilation points ..................................... ................................................ ............ 38

2.6 Injection pump .............................................. ................................................ ....................... 41 41

2.6.1 Operating principle direct injection Volvo Penta MD1 2.6.2 ................................................ .....................
Injection pump MD5 ................................................ ................................................... ................... 42

2.7 Spreader ................................................ ................................................... .......................................... 45

2.8 Refueling diesel .............................................. ................................................... ........................ 47 2.9 Fuel

consumption ....................... ................................................... .............................................. 47 2.9.1 Theoretical calculation

of fuel consumption .............................................. ..................................... 47

3. Lubrication system, oil in engine and drive ......................................... ........................................... 49

3.1 Oil change in the engine ............................................... ................................................ ........................... 49

3.2 Oil change in the 110S drive ........................................... ................................................ .................... 50 3.3 Oil

pressure ........................... ................................................... ................................................... ............ 50 3.4 Oil

leakage .................................... ................................................... ................................................. 51

4. The electrical system .............................................. ................................................ .............................. 52

4.1 Emergency start of the engine ............................................... ................................................ ....................... 54 55
4.1.1 In the event of an empty ................................................... ................................................... ..........................
starter battery 4.1.2 In the event of a fault on the key at the control
................................................... ................................................ .... 55
panel .................................... ................................................... ...... 55 4.1.3 If starting batteries ......................................
are almost empty 4.1.4 56 Start with the boa

4.3 Generator and starter motor .............................................. ................................................... ............ 57

4.4 Batteries................................................... ................................................ ........................................... 58 4.4.1 State of
charge of the batteries .. ................................................... ................................................... .... 58 4.4.2 The resting
voltage of the batteries ......................................... ................................................ ......................... 58 4.4.3 Consumption
voltage of the batteries ................... ................................................... ............................. 58 4.4.4 Battery
types ................ ................................................... ................................................... .......................... 59

5. The cooling system .............................................. ................................................... .............................

60 5.1 Overheating of the motor. ................................................... ................................................... .......... 60
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5.2 Thermostat ................................................ ................................................... ........................................ 62

5.3 Seawater pump, changing the impeller ........................................... ................................................... .65

5.4 Vacuum valve .............................................. ................................................... ................................ 68

5.5 The engine as an emergency pump ............................................... ................................................... ..................

70 6. Cylinder head ............................ ................................................... ............................................... 71

6.1 Changing the cylinder head gasket ............................................... ................................................ .. 71 6.2

Control tightening of cylinder head nuts ........................................... ......................................... 74 6.3 Valve

adjustment ...... ................................................... ................................................... ...................... 75

7. The exhaust system .............................................. ................................................ ....................... 77

7.1 Exhaust fumes .............................................. ................................................... ........................................ 77

7.2 Exhaust gas temperature sensor ................................................ ................................................... ............

78 8. Other engine controls ................................. ................................................ ........................... 78 9. Winter

preservation ................... ................................................ ............................................. 79 9.1 Purchase the

following new parts ................................................ ................................................ ............. 79

9.2 Warm up the engine, change the engine oil and filter.......................................... .......................................

79 9.3 Empty the water separator (if necessary, change all fuel filters) . ................................................... ............... 79
9.4 Fill the fuel tank full ............................................... ................................................ ............. 79

9.5 Take the boat ashore ............................................. ................................................ .................... 80 9.6

Change the oil in the 110S drive ...................... ................................................ ............................................ 80

9.7 Drain the cooling water and dismantle the thermostat ........................................... ....................... 81 9.8

Flush the cooling system with glycol ..................... ................................................... ............................. 82 9.9
Impeller .................. ................................................... ................................................... ....................... 82
9.10 Mount the thermostat ............................................... ................................................ ................. 82

9.11 Clean the vacuum valve ............................................... ................................................ ............ 82

9.12 Other controls .............................................. ................................................ ......................... 82

9.13 Dismantling the folding propeller ............................................... ................................................... .. 83

9.14 Winter setup ............................................. ................................................... ........................ 85 10.

Launching ...................... ................................................ ................................................... ... 86 10.1 Before

launching ........................................... ................................................... .............................. 86

10.2 When the boat is in the water ............................................. ................................................... .................... 86

11. Service after 50 hours of operation - or at least once per season .............................. 87
12. Service parts .............................................. ................................................... .......................... 88

13. Dimensions and tables ............................................. ................................................ .... 90

15. Spare parts and engine refurbishment ............................................. ...................................... 96

15.1 Volvo Penta spare parts .............................................. ................................................... ............ 96

16. Troubleshooting .............................................. ................................................ ............................. 99

16.1 If the engine stops or does not start ........................................... ........................................... 99

16.2 The motor panel alarms ............................................... ................................................... ................. 99

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1. Introduction

1.1 Preface

Our boat engine is a Volvo Penta MD5A marine diesel with sailboat drive. Engine and drive were
installed in 1978 by Birka Marin in Mariehamn Åland who built our sailboat.

When we bought our boat in the spring of 2004, we really thought that the engine was nothing
to count on and should be replaced immediately. But curious as you are, I started and "learned"
the engine. I'm actually surprised at how well the Volvo Penta MD5 engine is engineered.
It starts fine, runs like clockwork, is fuel efficient, takes up little space and is relatively
quiet for being a single cylinder. Now I have come to the conclusion that the MD5 is a completely
superb engine that has all the conditions to function for many more years.

This document is written for myself and my family to understand and operate the diesel
engine in our boat. I have tried to write so that you don't need to have any special knowledge
about how a marine diesel engine works. Over time, it has become more and more and now
the document is very comprehensive. We now no longer have any boats with MD5 left and
therefore this document will no longer be updated.

You could probably say that this is a complete document for how to take care of a VP MD5
engine. The content applies mainly to the MD5A and MD5B with 110S drives, but should
also largely apply to the MD5C.

The document goes deeper than the instruction manual and many details are shown in
pictures. Here is probably everything you need to know for normal use, normal service and
simpler repairs. But if you want to refurbish the engine, I refer to Volvo Penta's workshop manual.

If someone else wants to share the contents of this document, that's fine. I
recommend having a printed version handy in the boat. BUT I take no responsibility for
any damage that may occur due to of inaccuracies. The information has been compiled to
the best of our ability and is therefore used entirely at the reader's own risk. The material
consists of own texts, images and information from Volvo Penta's instruction books.
Contributions also come from several readers, for which I am grateful.

I find it hard to believe that Volvo Penta has anything against someone compiling this information
for an old engine that is no longer being sold. From my side, the material may be
distributed freely provided that it is not changed or sold. I hope it can be of use to other
MD5 owners. If you, as a reader, have opinions and constructive suggestions for improvements,
please send me an e-mail.
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Sources:
• Volvo Penta Product Bulletin MD5A/110A Publication 6994, published 1976 •
Volvo Penta MD5A Workshop Manual, Publ No 3061, published Dec 1975 •
Volvo Penta MD5A, MD5B, MD5C Workshop Manual (Swedish), published 1998 •
Volvo Penta Instruction Book MD5A/ 110S, Publ No 2955A, issued 6/1977 • Volvo
Penta Addendum to instr. Book 2955, ventilation MD5A, publ no. 3447, published 1976 •
Volvo Penta Maintenance instructions. Addendum to instruction book publ no 2955. Publ No 3224A published March
1976 • Volvo Penta MD5A-110S Instruction book, Publ No 2956A, published 1978 –
2 • Volvo Penta Do it yourself Manual, among others MD5, Publ no 3805,
published 1982 • Volvo Penta Instruction Book MD5B/110S, Publ No. 2955 issued 1980-8, with supplement for MD5C/120S, Publ No. 4056 issued
1981-9
• Volvo Penta 110S Sailboat drive, Workshop Manual Publ no 3439, published 1978
• Various information from the Internet and Volvo Penta mechanics

Stefan Fors,
Västerås, Sweden
Civil Engineer
e-mail: stefan"nospam"broach.se (replace "nospam" with @ to email)
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Update information

2009-11-15 Small text corrections

2008-08-10 Fixed typos (never published)
2008-08-08 A correction about mounting propellers. Correction of image reference. More on unexplained
cooling problems.
2008-05-08 Some small changes, among other things, about the high-pressure pump and about thermostat mounting.
2007-08-18 Various small updates. Pointing out in the event of a stolen connection if you have
fresh water cooling. New feed pump as Volvo Penta has stopped manufacturing the "old standard".
2007-06-14 More information about the function of the vacuum valve. More information about MD5C.
Sketches of Volvo Penta's two-bladed bronze folding propeller.
2007-04-19 Manufacturing code for impeller, note on the importance of the thermostat housing for
proper cooling. The engine as an emergency pump. Tips on how to secure the rubber gasket in
the fine filter. Various minor updates and fixes.
2007-02-10 Threads for sensors, various updates
2006-11-10 Some minor updates 2006-10-05
Updates, more spare parts information 2006-08-31 More on
oils 2006-08-28 More on
valve adjustment 2006-08-25 Updates
among others injection pump and injector 2006-08-14 new exploded
views, more about fuel pump and injection pump 2006-05-12 Several updates were
made 2005-08-22 First version ready for
general distribution.
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1.2 Principle for 4-stroke diesel

Almost all diesel engines used in recreational boats are of the 4-stroke type. In the past, there were also 2-
stroke diesels, and before that it was ball-ignition engines that applied. The principle of a 4-stroke diesel engine
is simple and similar to a 4-stroke petrol engine. On a diesel engine, you only regulate the fuel supply, i.e. the
engine is constantly working with too much air. The air is admitted through the intake valve which is
compressed and becomes hot. The fuel is injected into the compressed air and ignites "by itself". On a petrol
engine, a mixture of air and fuel is admitted which is then ignited with a spark from the spark plug.

• Stroke 1, The piston goes down: Air is drawn in via the intake valve which opens. Note that
only air and no fuel is taken in via the valve

• Stroke 2, piston moves up: All valves are closed. The air trapped in the cylinder is pressed together and
compressed. When air is compressed it becomes hot. The moment before the piston reaches its highest
position, diesel is injected via the injector.

• Stroke 3, piston goes down: The diesel injected into the hot air is ignited. When the diesel "burns", an
expansion takes place that pushes the piston down.

• Stroke 4, the piston moves up: The exhaust valve opens and the exhaust gases are forced out
of the cylinder. When the piston reaches its top position, the exhaust valve closes.

On a decent low rev single cylinder engine like the Volvo Penta MD1, MD5 and 2001, you can actually count
the number of "bangs" and then multiply by 2 to get the idle speed for the same time period. Now you may
not be able to count for a minute, but try counting for 10 seconds. If you're fast, you might manage to count to
maybe 60, first multiply by 6 to get the number of "thumps" in 1 minute and you get 360. Then you
double and then the engine runs at about 720 revolutions per minute.
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1.3 General description of the engine

The MD5 is probably a very good marine diesel engine. If you have such an engine, take good care
of it and it will hopefully last for many more years. MD5 is simple and robust. Engine block and
cylinder head are made of cast iron. The valves are controlled by good old pushrods. Both feed
pump and injection pump are mechanical. According to hearsay, the 110S drivetrain
should also be very good, it is said to last 2 – 3 engines.

A marine diesel engine does best with a lot of driving. When the engine is running, it should be
properly warmed up and run at a relatively high load, preferably 1 hour or more at a time.
But you almost never do that in a sailboat, so sooner or later there can be problems.
The engines are simply used too little and are broken down from the inside by corrosion.

To tinker with a diesel engine, you have to learn some basic things and have some tools. Get some fixed
wrenches and avoid the wrench that just destroys. Read this writing, instruction books, look for information
on the Internet, ask others, work methodically and be careful. If anything is unclear, contact an authorized
Volvo Penta dealer or someone knowledgeable about engines. To avoid downtime and to "avoid"
changing the engine, you can make a little effort to give the engine the longest possible lifespan
before you decide to invest in a new engine.

The MD5 is a small single cylinder direct injection diesel engine that was produced in the years 1975
– 1982. The engine was produced in three variants, MD5A, MD5B and MD5C. 5,000 engines were
manufactured in Norway by Mandals Motorfabrik, which was a subcontractor to Volvo. They are said to
have manufactured just over 20,000 engines. As there are MD5C engines with serial numbers >
30'000, it can be assumed that there is quite a large "gap" in the serial numbers. It may be that MD5a and
MD5b have serial numbers up to roughly 20'000 and that MD5c has serial numbers from 30'000. It
seems that there are very few MD5Cs.

The only differences between the MD5A and MD5B seem to be the motor mounts. The MD5C gives more
than 25% more power and differs slightly in the fuel system, injection pump, fuel lines, leak
oil pipes, pistons, frame bearings, connecting rods etc. The MD5A and MD5B have the 110S sailboat drive
and the MD5C has the 120S drive. You can exchange an MD5A for an MD5B or vice versa, but it is not
possible to exchange with an MD5C. Probably without too much work you can change from MD5C to a 2001
engine and use the same drivetrain. There is no possibility to change from 110S drive to 120S drive
or vice versa as the connection between motor and drive is different. Note that there are two gears on
the 110S drivetrain.

The displacement is 0.45 liters, the power is 7.5 hp on the propeller shaft, the speed is a maximum of
2500 revolutions. The MD5C has the output increased to 9.5 hp at 3000 rpm. Note that Volvo Penta states
the power on the propeller shaft, which is different from other manufacturers that state the
crankshaft power. To compare, you therefore have to add maybe 10% to get fair values to compare with.
One can therefore assume that the MD5A/B produces 8.25 hp and the MD5C produces 10.45 hp on the
crankshaft.

Engines with recoil can be cranked and therefore have decompression handles. With this handle, you
can "open" a valve on the cylinder so that the compression disappears.
You can then "spin up" the engine and by closing the valve you can, with a bit of luck, get the engine
started. If you have S-drive, there is no possibility to crank the engine. All MD5As have decompression
handles, some MD5Bs and MD5Cs have the handle, unclear how Volvo intended.
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The injection pressure, i.e. when the fuel is injected into the cylinder at high pressure, is 180 kp/
cm2 ( = 17´700´000 N/m2 or Pascal = 178 bar). Compare this to a modern diesel engine in
the mid-2000s with electronic direct injection operating at an extremely high pressure of about
2000 bar. The advantage of extremely high pressure is that you can burn more fuel and
thus produce more power without increasing the engine's weight while reducing the amount of
soot. The disadvantage is that the tolerances are reduced, so you cannot tinker with the engine
yourself, which means increased costs over time and that there will be extremely high demands
on the purity of the fuel. After all, the fuel consumption in an MD5 is low and if you save maybe
10, 20 or 30% of the fuel in a modern engine, it really plays a secondary role.

Consumption for the MD5A and MD5B is only 1 liter per hour. An MD5C should consume 1.25
liters per hour. I would probably rather have a simple engine with slightly higher
consumption than a modern one that risks expensive repairs due to that you can't do anything
yourself but have to pay a mechanic. In addition, with a modern high-pressure diesel, you have
to be even more careful with the cleanliness of the fuel (correct filter, clean tank, etc.) My
conclusion is that a new modern engine has lots of advantages such as lighter, quieter,
more fuel-efficient, less emissions, etc., but you have to realize that the lifespan is shorter and
that ironically you need more "professional service" which costs money. An old MD5 is
relatively easy to service yourself.

Engine rpm 700 1000 1500 2000 2500 Propeller rpm

422 602 904 1205 1506 Figure 1.2 table showing the
ratio of engine to propeller rpm for 110S driven with the ratio 1:1.66
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1.4 Description of how the engine works

Diesel is refueled in the fuel tank. A fuel line leads the fuel from the tank to the pre-filter with water
separator in the engine compartment. From the tank there is also a venting hose that opens out near
the filling hole. The vent hose's task is to continuously ensure that air enters the tank to replace the
fuel that is sucked into the engine, otherwise there will be negative pressure in the tank and after a while
the negative pressure will be so great that there will be a stop in the fuel supply. The pre-
filter must be changed once per season. It happens that the venting hose has been plugged
and then you get negative pressure in the tank and stop the engine after a while. Easily checked by
driving with the fuel cap open, just make sure no water can get in.

After the pre-filter comes the feed pump (fuel pump). The feed pump is equipped with a hand pump so
that fuel can be manually pumped to vent the system. There is a strainer in the feed pump that
must be cleaned once a season. The feed pump sucks the fuel all the way from the tank via the
pre-filter. This is why it is so important that all hoses and connections are 100% tight. The smallest hole
and air will be sucked into the fuel system and the engine will stop. This side of the fuel
system is called the suction side. The other side that leads to the fine filter is called the pressure
side. If there are leaks on the pressure side, it is noticeable by simply leaking fuel.

After the feed pump comes the fine filter which removes the finest particles so that they do not reach
the injection pump and the spreaders. On MD5A and older MD5B, the fine filter is complicated with
several parts and a loose filter element, on newer MD5B and all MD5C it is much simpler and looks
like a normal oil filter. The fine filter must be changed once per season.

After the fine filter, the fuel is led on to the injection pump, also called the high-pressure pump.
The injection pump builds up a really high pressure and via a metal pipe the fuel is pushed to the
injector. The injection pump on the MD5 is controlled by the camshaft and pumps fuel at high
pressure at exactly the right time to the injector.

The injector injects fuel into the cylinder at the moment of ignition. At the moment of ignition, there is
hot compressed air which has been let into the cylinder via the air valve via the inlet valve and then
compressed by the cylinder. The compression pressure is around 20 bar. In the distributor there
is a spring-loaded needle valve that opens with the help of the fuel pressure from the injection pump,
the opening pressure is just under 180 bar. The injection takes place just before the piston reaches its
turning position. When the fuel pressure drops, the needle valve closes with the help of its spring force.
Diesel and the hot compressed air ignite and push the piston down. You notice that there is a
fault with the spreader mainly through reduced engine power.
The spreaders should be checked at regular intervals.

The injection pump has a complicated structure that requires special tools and special measuring
equipment. Service and overhaul of the spreader and the injection pump is handled by a specialist.

The excess fuel that is not forced into the cylinder is routed through a thin metal tube called a
leak oil tube, back to a location between the feed pump and the fine filter. There is no return line
back to the fuel tank as it does on more modern diesel engines.
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The valves must be adjusted and the cylinder nuts must be retightened at regular intervals. The reason
for a check pull is to make sure that it does not start to leak between the cylinder and the cylinder head.
If there is a leak, there is a high risk that the top will be warped and will have to be renovated.

The engine is water-cooled. Most of the engines were supplied with seawater cooling. Freshwater
cooling can be retrofitted. The cooling water intake is on the BB side of the 110S drive.
The seawater pump sucks water and pumps it on to the thermostat. In the seawater pump there is a
pump wheel called an impeller. The impeller requires annual inspection. The thermostat lets water
into the engine if it needs cooling. The water finally mixes with the exhaust gases and cools.
The water that the thermostat does not allow into the engine goes directly to the exhaust stack. The
mixing of hot exhaust gases and cold cooling water takes place in the exhaust manifold, which is made
of cast iron. The mixture is then led in a rubber hose to the muffler and out of the boat via a "gooseneck".
It is important to keep an eye on the exhaust so that water really "bubbles" out when the engine is
running. If cooling is stopped due to rubbish, you risk a fire in the rubber hose for the exhaust
gases.

To prevent the engine from being "drowned", there is a so-called vacuum valve in the cooling system. In
some situations, there can be a siphon effect and the cooling water continues to flow through the cooling
system even though the engine is switched off. If the exhaust valve is open at the same
time as the water fills the exhaust system, there is a risk of getting water back into the cylinder.
The engine can then break down. With an engine with more than 2 or more cylinders, the risk of
destroying the engine is greater. If the engine fires on 1 or more cylinders, the crankshaft is guaranteed
to be destroyed as the water in the water-filled cylinder cannot be compressed. This can also occur
for engines with an internal cooling system, so-called freshwater cooling.
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1.5 How to run the engine

Many marine diesels are driven far too smoothly, with the result that the piston rings seem to stick in
the piston ring grooves. Two piston rings (compression rings) keep it tight and the third ring is the oil
scraper ring which is a little different. If the compression rings stick, the compression may be bad,
which can be checked by loosening the spreader, spraying some engine oil into the cylinder,
and then taking another compression test. If the oil scraper ring works as it should, the engine draws
minimal engine oil. The job of the oil scraper ring is to press the lubricating oil down into the
crankcase so that the oil does not burn in the cylinder.

According to Volvo Penta, the MD5 should be able to run at a maximum speed of 2500 rpm (MD5C
3000 rpm) if you have the right propeller. This means that you should be able to reach the
maximum speed with the right propeller, but you should never actually drive at the maximum
speed.. The engine then runs optimally at all speeds. The rule is that a marine diesel must be
run at approx. 80% of the maxv agreement, for MD5A/B it will be approx. 2000 revs, for MD5C
it will be approx. 2400 revs. Since the engine is old, you can go a little lower, perhaps at 75%.
You can pull at full speed for a little while sometimes. You should not set the cruising speed
TOO low for any length of time. You should try to drive close to full throttle for a few minutes every
other trip when the engine is warm. You even rev up considerably with the gear in the neutral
position to the maximum speed so that the piston rings will rattle free from the groove in the
piston due to the acceleration forces. Of course, you can simmer slowly at the idle speed so-
called "forward idle" when driving in and out of port, but you should not do that for a long time.
If you drive at too low a load, you may experience something called "cylinder
polishing". Then the sealing surface between the piston rings and the race becomes far too
smooth, and loses the ability to hold lubricating oil. The oil is needed to lubricate, reduce friction,
seal and conduct away heat.

Run the engine at 70 - 80% of full speed, ie 1700 - 2000 revolutions (MD5C 2100 - 2400 revolutions).
Realize that even an MD5 is old and should not be overworked to last many more years.

1.6 Lifespan

In the magazine Praktiskt Båtägande no. 1 2005 it is stated that it is a truth with modification that a
diesel engine can run as long as desired, this only applies to engines that are basically never switched
off. The lifespan of a diesel engine depends on the number of cold starts. The more cold starts,
the more the engine wears. In addition, it is the idling at the boat site that slowly kills the engine
because it is constantly affected by internal corrosion.

As for the lifespan of an MD5, we don't know how long it will last, probably with the right
maintenance and renovation it can work for many more years. Everything has proper dimensions
and if something breaks, it can almost always be repaired.
Of course, there are boat owners who have changed to a more modern engine because of
breakdowns. There are boats from the early 60's that still have their MD1 engine, so an old marine
diesel engine can last a long time just take care of it.

What slowly destroys a diesel engine is rust attack "from within". The cylinder head is
the first thing to break. It pays to change the cylinder head before it breaks, otherwise there is a risk
of a "general race". On our own Volvo Penta MD5 was changed
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the top cover in 2001. Perhaps you should change it after 25 - 30 years or at least unscrew it and
let a mechanic inspect the top?

To avoid the engine being destroyed, the most important thing is to do proper
winter preservation. It may be useful to install a fresh water cooling. The advantage is that you
circulate fresh water and that in a closed system the water's oxygen "disappears" after a while.
Salinity and the oxygen content of the water are decisive for rust attack. Before installing a freshwater
cooling system, the entire cooling system must first be thoroughly purged. Now, however, one must
be careful when installing a fresh water cooling system on an old engine that has been used in salt
water. The reason is that in the beginning (for a few years), particles and other debris that sit in
the cooling ducts are constantly loosening and clogging the heat exchanger, causing the engine to overheat.
The company Martec has as an extra option for its fresh water cooling systems a small filter that
collects rust flakes. You can then quite easily continuously collect rust layers before they clog
the heat exchanger. A fresh water cooling costs SEK 5,500 in the region to buy + assembly.
We have chosen not to buy freshwater cooling because the boat has been in freshwater (Mälaren)
since 2004, except for a few weeks when we sail in the Baltic Sea.

The MD5 has no electronics to mess with, you can say that it is a fully mechanical engine that is
very robust and simple, giving it a long life and good running economy.
There is only 12V to turn on a relay to drive the starter motor. The engine is then started (ignites)
solely due to of the mechanical compression. You can even start some MD5s by hand if you have
no power in the battery. However, it is only in the version with reverse that has a hand crank,
strangely this function is not available on the MD5 which was delivered with s-drive.

There are two simple sensors (water temperature and oil pressure) with the simplest
imaginable functionality. When the temperature gets too high or the oil pressure drops, the
sensor becomes "short-circuited", like a simple on/off button. A current then flows through a
buzzer and through a lamp. The buzzer sounds and the lamp lights up. The system is based on the
buzzer sounding when the light is on. If the lamp breaks, nothing is heard from the buzzer.

An MD5 motor lasts a long time, even if it has a little rust on the outside, it does not affect the
function on the inside. If the engine starts easily and runs well at all revs, there is no need to do
anything other than normal service.

Volvo's sailboat gears 110A are basically indestructible provided you change the oil and ensure that
no seawater penetrates through the oil plug at the bottom. Therefore, replace this gasket every
few years. According to some engine people, the 110S drive should hold 2 - 3 engines.

The advantage of using Volvo Penta engines is that there is plenty of service around
Sweden's coasts, but you can hardly expect any help during the holidays when customers are
queuing and you have a mechanic on holiday. The downside is the price, as Volvo Penta is
expensive for everything and you always get a feeling in your stomach that Volvo Penta
dealers are a bit cocky.
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1.7 What you can do yourself on the engine

What you can do yourself without any major problems is to change the fuel filter (pre-filter and
fine filter), clean the water separator, clean the fuel strainer, change the thermostat,
check the vacuum valve, change the impeller, air the fuel system, change the engine oil and oil
filter. Furthermore, it is relatively easy to adjust the valves. The cylinder nuts (the cylinder head
nuts) must also be checked.

What you have to be able to do yourself is to bleed the engine, with this writing it should
be relatively easy even for the beginner.

If you feel confident with the block keys, you can actually manage to tear down and reassemble
most of the engine.
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1.8 Pictures and exploded views

Pictures 1.3 and 1.4 show MD5A with 110S
drive.
Picture 1.5 and 1.6 shows MD5A with reverse
stroke, Picture 1.7 shows all parts of the fuel
system for MD5A and
MD5B Picture 1.8 shows the parts
of Bosch injection
pump Picture 1.9 shows
regulator with mounting details.
Pictures 1.10, 1.11, 1.12 and 1.13 show the
110S drive.

1. Console for control cable 2.

Lever for shifting 3.
Seawater pump 4.
Fuel filter, also called fine filter 5.
Decompression handle.
6. Fuel pump, also called feed
pump 7.
Engine oil filling 8. Alternator
9. Starter motor
10. Elastic
engine suspension 11. Zinc ring 12.
Intake
silencer with filter 13. RPM lever 14. Water-
cooled exhaust bend
15. Bed 16. Seal between
bed and
drive 17. Cooling water intake 18 Shut-
off valve for incoming
cooling water Pictures 1.3 and 1.4 show an overview of
MD5A with 110S drive
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Pictures 1.5 and 1.6 show an overview of the MD5A with reverse gear (gearbox).
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Figure 1.7, Exploded view of the fuel system for MD5A and MD5B.
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Parts list picture 1.7 fuel system MD5A and MD5B.

Ref Description Article No. Quantity

0 Washer 840210 4
Spec 867452 engine 22579 -, spec 867339 engine 19951-, spec 867539 engine 20838-.
0 Gasket 840210 2
Spec 867452 engine 22579-, spec 867339 engine 19951-, spec 867539 engine 20838-.
0 Plug 960630 2
Spec 867452 engine 22579-,spec 867339 engine 19951-., spec 867539 engine 20838-.
1 Injection pump 2 16 496
Screw 3 957178 1

Resilient washer 4 833323 33

Gasket, thickness 0.2 mm 5 942001

Injector (replaced by 838289) 941906 1

5 Injector 5 942353 1

Injector, replacement 838149 1

6 Stud screw 25167 2

7 Plate 957178 3

8 Washer 840532 2

9 Lock nut 10 2

Pressure pipe 1

11 Leakage oil 1

pipe 12 Screw (included in 838153) 1

13 Gasket (included in 838153) 2

14 Hole screw 1

14 Gasket 16 2

Hole screw 1

17 Gasket 18 2

Fuel pump 19 1

Screw 20 2

Spring washer 21 O- 2

ring 22 1

Fuel pipe 23 1

Hole screw 24 1

Gasket 25 41

Fuel filter (Fine filter)

(829912) NOTE newer fuel filter for: Spec 867452 engine 22579 -, Spec 867339 engine 19951-, Spec 867539 engine 20838-.
25 Fuel cleaner (Fine filter) 803323 Spec 867452 engine -22578. Spec 867339 engine -19950. 1
Spec 867539 engine - 20837. Replaced by 829912.
26 Screw, length = 25 mm 959238 Spec 867452 motor -22578. Spec 867339 engine -19950. Spec 2
867539 engine -20837.
26 Screw, length = 30 mm. 959239 2
Spec 867452 engine 22579-. Spec 867339 engine 19951-. Spec 867539 motor 20838- 27 Spring
washer 28 Nozzle 29 941908 2

Hole screw 30 807059 1

Hose 31 807058 1

Gasket 32 838208 1

Hole screw 33 11994 2

Seal 34 Screw 803658 1

(233017) 11991 1

240664 1

35 Hole screw 25167 1

36 Gasket 37 957178 2

Fuel hose (838205) is replaced by 840263 38 Nipple 840263 1

39 Hose 833922 1

connection 40 Nut 41 829744 1

Fuel pump 807061 1

42 Fuel tank 43 833454 1

Regulator (see
picture 1.9)
44 Water separator (CAV)
44 Filter, Pre-filter(875542) 829764
45 Gasket 46 957176 12

Nipple 47
Attack nut

Note that No. 41 is an additional fuel pump that I have never seen. You might be able to put an extra electric diesel
pump here.
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Picture 1.8, Exploded view high pressure pump - injection pump Bosch 838150 for MD5A and
MD5B. NOTE MD5C has a different injection pump.
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Parts list picture 1.8 high pressure pump Bosch 838150 for MD5A and MD5B.

Ref Description Article No. Quantity

0 House
1 Injection pump 838150 1

3 Holder 243420 1

4 O-Rings 239989 1

5 Plug 870576 1

6 Adjustment washer T=0.5 mm 241734

6 Adjustment washer T=0.3 mm 238312
6 Adjustment washer T=1.0 mm 238314
7 Spring 238309 1

8 Packing 870581 1

9 Valve 838237 1

10 Pump element 838230 1

11 Pin 12 243423 1

13 Pins 243422 1

14 Screw 870007 1

15 Call 243415 1

16 Sleeve alto, D=18, 85 mm 243418 1

16 Sleeve alto, D=18.70 mm 243417 1

17 Tray 870023 1

18 Spring 870022 1

19 Tray 870788 1

20 Lifters 870796 1

21 Lock pin 870004 1

22 Bushing 870789 1

23 Roll alt, d = 14.04 mm 243193 1

23 Roll alt, d = 14.16 mm 243194 1

23 Roll alt, d = 14.28 mm 243195 1

23 Roll alt, d = 14.40 mm 243196 1

23 Roll alt, d = 14.52 mm 243197 1

23 Roll alt, d = 14.64 mm 243198 1

23 Roll alt, d = 14.76 mm 24 3199 1

23 Roll alt, d = 14.88 mm 243200 1

23 Roll alt, d = 15.12 mm 243201 1

23 Roll alt, d = 15.24 mm 243202 1

23 Roll alt, d = 15.36 mm 243203 1

23 Roll std d = 15.00 mm 243206 1

24 Bleed screw, engine 3809 - 240664 1

25 Gasket, engine 3809 - 25534 1

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Picture 1.9, Exploded view regulator with mounting details for MD5A and MD5B
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Parts list picture 1.9 regulator for MD5A and MD5B.

Ref Description Article no. Quantity 838144 1

1 Regulator 838064 1 838075 1
4 Gears 963008 1 181180 1
6 Sleeve 914449 1 838168 1
7 Locking screw 838215 1 941670 1
8 Ball bearings 907824 1 941907 1
9 Lock ring 951671 1 838257 1
10 Lids
11 Bracket
13 Tray
14 Scissor stick
15 Resilient washer
19 Track riders
20 Lever arm
Previous version of lever arm 838087 + screw 955270 is replaced by lever arm 838257 + screw 949235
21 Screw, previous version 955270 1

22 Screw 192244 2

23 Dice 833133 2

24 Tray 955892 4

25 Scissor stick 907824 2

26 Tension pin 951951 1

28 Screw 949330 1

29 Rubber ring 925052 1

31 Hävarm 838082 1

32 Screw 942001 1

34 Nut 955781 2

35 Kulled 813042 1

36 Resilient washer 941905 1

37 Nut 951784 1

38 Screw 942001 1

39 Sleeve 838173 1

46 Tram rider 951670 1

49 Lock nut 946577 1

50 Pipe rod 951926 1

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Picture 1.10, 110S Drive

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Picture 1.11, Exploded view 110S upper part

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Picture 1.12, Exploded view 110S lower part

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Picture 1.13, Assembly details 110S

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2. The fuel system

2.1 General about fuel systems

The fuel system is very sensitive to leaks. If air gets into the hoses, the engine can stop. Two types of leaks
can be distinguished. The first type that is the most difficult to find are the ones before the feed pump. Since
the feed pump sucks fuel all the way from the tank, you can't see where it's leaking. Leaks after the feed
pump are much easier to see when fuel is pushed out, it leaks and drips diesel.

After intervention in the fuel system, check after starting that there is no fuel leakage. If fuel
comes out, air always comes in in some mysterious way, which leads to malfunctions. If fuel comes out, there
is always a small risk of fire.

There are two fuel filters (pre-filter with water separator and fine filter) and a fuel strainer in the feed pump.

When checking and servicing the fuel system, it is important to be thorough.

It is especially important that no dirt gets into the very sensitive fuel system.

You should have a fuel hose with an 8 mm inner diameter from the tank to the engine compartment. Our boat
used to have a 6 mm hose that was changed in 2006. Because the connection nipple on the tank, we chose in
consultation with Volvo Penta's representative in Västerås to continue with 6 mm hose.
An MD5 uses very little fuel and if it has worked for less than 29 seasons, we continue in the same way as
before.

Spare filters must always be in the boat.

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filter with water separator - Extra fuel filter

Sits as the first filter from the tank. Cleans any water from the fuel and the worst debris from the diesel oil. See
pictures 2.4 and 2.5.

The water separator is transparent so that it is easy to determine whether there is water in the fuel. In that
case, water is in the bottom of the container and can easily be drained out through the drain in the
bottom. Open the white plastic screw at the bottom and let the water and fuel drain into a mug. NOTE fuel
spillage.

To determine whether there is water or fuel in the mug, drop a few drops of water.
You then clearly see how diesel and water differ (provided there was only diesel in the mug).

The pre-filter is changed every year.

When changing the pre-filter, loosen the center screw that holds the filter and container together with an 11 mm
spanner (see picture 2.1). Put in new gaskets, new filter and tighten the package with the center screw. Aeration
point 1 is located at the pre-filter. If it is natural from the tank, you can bleed here, if the tank is lower and the engine
has a suction feed pump, which all MD5s have, do not touch this venting point as you only let air in here. It is
possible to imagine filling the tank completely so that there is self-pressure at the pre-filter.

After replacement, the fuel system must be bled. See section on aeration.
If you have additionally equipped your boat with an electric fuel pump between the tank and the pre-filter, you
can vent at the center screw.

Picture 2.1, The upper part of the pre-filter holder (CAV) which was installed in the summer of 2006. Note that
you should never poke the breather screw if you have a suction pump at the engine, which all MD5s have.

See chapter 12 for the article number and price of the filter.
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Picture 2.2, Pre-filter, here you can see where the O-ring, which is about 2 cm in diameter, sits. In the outer
groove you can see one of the large O-rings. In the middle the small O-ring. .

When you change the pre-filter, it comes with a set of O-rings (gaskets) that must be changed at the same
time. I always wondered where the second smallest O-ring would sit. One beautiful summer day I
got the answer. On the underside of the upper "lid" where it sits, see picture 2.2.
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If the fuel line is empty.

If the fuel "flows back" to the tank, it is difficult or even impossible to hand pump with the hand pump on
the feed pump. Man e.g. can connect a hand pump for outboards and draw fuel. Be sure to
collect the fuel in a bowl. The easiest way is to detach the hose before the fuel pump and place the hand
pump directly on the fuel hose, see picture 2.3.
You can also fill the tank to the maximum so that there is "pressure" from the tank. You then avoid
hand pumping.

Figure 2.3, Shows where you can connect an

extra hand pump to draw fuel from the tank.

NOTE Do not confuse this with the fixed

manual hand pump on the feed pump.
The white filter looming is the engine oil filter.

Figure 2.4, Changing the pre-filter with water separator

Picture 2.6, pre-filter, glass body with

white drain tap at the bottom to drain water. In
the picture, the glass body is filled with fuel
from Finland. Normally in Sweden, the fuel
Figure 2.5, pre-filter with venting point 1 is more or less crystal clear.
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2.3 Fuel pump - feed pump

Pictures 2.7 and 2.8 show what the feed pump looks like. The pump sucks fuel from the tank.
There is a strainer (filter) under the cover of the fuel pump which must be cleaned every year.
Use an 8mm spanner to unscrew the small bolt. Be prepared for fuel spillage when removing the
cap. Be careful with the position of the filter so that it comes back the right way. See picture 2.8.

When reassembling, a little loctite or similar sealant may be needed to make the cover completely
tight. Note the position of the strainer before removing it. Clean the strainer and wipe any dirt
from the housing and cover before reassembling the fuel strainer. The fuel system must be bled
before the engine can be started.

In the feed pump there is a pump membrane that can break, first it pumps poorly then not at
all. If the diaphragm breaks, there is a risk of diesel being pumped into the engine, which
is mixed with the lubricating oil. Therefore, you must check the oil regularly and be observant.
If the oil level increases, when it is full, there is a risk of oil entering the cylinder. The engine
then starts to run on the lubricating oil and will run out of control. The only way
to stop the engine is to use the decompression handle, if there is
no attempt to block the air supply. If the engine is not stopped, it is guaranteed to cause
engine damage, over-revving or it will cut when the lube oil runs out.

If the feed pump is worn out, and in about 30 years you use up maybe 2 - 3 pumps, then according
to Drevia in Lysekil it can be a "round trip" on the air. The only way to get things sorted is to replace
the feed pump.

Picture 2.7, new feed pump (fuel pump) before assembly. When changing, you must also put a new
O-ring against the engine block. The hand pump is used for manual pumping (hand pump) when
aerating.
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Figure 2.8, feed pump (fuel pump) with handle for manual pumping (hand pump) when venting.

Picture 2.9, strainer in the feed pump to be cleaned in connection with filter replacement, you can
see the black o-ring that seals against the engine block on the far left of the picture.
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Image 2.10 Feed pump spare parts

1 Feed pump Feed pump 2 Feed pump set Feed pump kit 3
Gasket Gasket 4 Membrane Part no 834255-2
Diaphragm 5 Sieve Strainer 6 Screw
Part noScrew
Screw 7 Gasket Gasket 8 Screw 418948-6
When mounting the
pump, a new O-ring must be mounted against the engine block.

Part no 15521-8

It seems that Volvo Penta has stopped making feed pumps (2007) but Drevia in Lysekil has
a replacement pump that fits and is also much cheaper.
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Figure 2.11, overview of the fuel system showing where vent points 2, 3, 4, 5 and 6 are
located. Note that vent point 4 is not on our engine.

I am thinking of rebuilding the fuel system, as follows:

1. Get an electric fuel pump that is mounted between the tank and the pre-filter, available
buy at e.g. Biltema.
2. Buy a more modern diesel filter holder that mounts on the wall in the engine compartment.
Remove the current old fine filter with holder and everything. Cut the metal pipe
(diameter 10mm) that goes from the feed pump, save as long a part as possible to be able to
thread on a rubber hose. The alternative is to get a coupling (I think it's called a banjo coupling)
with a machine connection to make it completely tight. Then extend the hose on the other
side of the fuel filter. You then avoid the mess with the insert filter and have made a small,
light modernization of your old engine.
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2.4 Fine filter - Fuel filter

The fine filter must be changed every 100 operating hours or once per season. According to
Seawolf (well-known boat guru signature on the Internet), it is enough to change at intervals of 10 years.

See chapter 12 for article number and price.

See pictures 2.11, 2.12 and 2.13. Be prepared for fuel spills. One tip is to put a plastic bag
around the entire metal cup to catch the diesel oil. Loosen the center screw and carefully lift down the
filter container (full of fuel). Remove the insert and discard it.
Clean the bottom of the bowl. Insert a new filter insert.

It is a bit fiddly to secure the gasket (image 2.13 no. 5). This particular gasket is a notorious source of
failure, so care must be taken here so that it does not leak diesel or, above all, that it does not leak air. The
gasket must go into a groove on the underside of the holder and it is difficult to get it in place as it likes
to fall down. A tip is to grease the rubber gasket (5) and push it up into the groove on
the underside of the holder. Then push the container (2) up from below into the groove of the
holder and tighten the filter with the bolt (1).
Bleed the fuel system before starting.

It is an old design with a loose filter insert that is in all MD5A and early MD5B.
In newer versions of the MD5B and all MD5Cs, there is a more modern filter that functions like a normal
oil filter without an insert. You can also rebuild the filter holder so that you get a newer model if you
think the old one is too cumbersome.

Figure 2.12, replacement of fine filter insert

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Picture 2.13, the parts of the fine filter

2.5 Venting the fuel system

The fuel system must be vented in the following

cases: • In all interventions in the fuel system when fuel has leaked, eg. when
changing the filter. • Running the
fuel tank empty. • If the engine has stopped in heavy seas because the engine has sucked air instead
fuel.
• In the event of long-term operating interruptions.

Bleeding means loosening a screw or nut and pumping until clean fuel comes out,
then tightening so that it is tight. Figure 1.1 shows an overview of where the various parts of the
fuel system are located.

Air according to the scheme below in order (lowest number on the air point
first). The most difficult are ventilation points 5 and 6, which are a bit tricky to both
open and close. So start with the other airing points. After each airing, a start attempt is made.
If the engine starts and runs well, the bleeding is complete. It simplifies if there are two
people so that you don't have to jump up and down between the engine compartment and the
ignition key in the cockpit. You probably have to do several airings. One reason for this is the
return line from the distributor which leads excess fuel back to the fine filter. If air enters
this line, air also returns to the fine filter.

Equipment and tools needed:

- Cloth to collect fuel spills, possibly a disposable cup. It can also be good to have a container
to collect diesel and rags in to avoid stains on the interior.
- Fixed spanners:
o 19 mm ring spanner: Bleeding point 5 o
17 mm ring spanner: Bleeding point 6, 7 o 14
mm ring spanner: Bleeding point 1 (should not actually be bled) o 10 mm
ring or joint spanner: Bleeding point 2, 3 and 8
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mm ring or socket wrench: To open the strainer on the feed pump

Suggestions on how the engine can be aired, make starting attempts between each airing attempt

Bleed 1:
Bleed first only at the absolute simplest and most important bleed screw, bleed point 2 (fuel filter).

Bleed 2
Repeat to only bleed at bleed point 2 (fuel filter).

Aeration 3:
Aerate the other "simple aeration points", increase with aeration points 3 and 8, i.e. vent at vent points 2,
3 and 8.

Aeration 4
Repeat to only aerate "the simple ones", i.e. at vent points 2, 3 and 8.

Aeration 5
Now increase with the aeration points 7.
Vent at vent points 2, 3, 7 and 8.

Aeration 6
Repeat the same aeration points as in aeration 3.
Vent at vent points 2, 3, 7 and 8.

Aeration 7
Increase with the "difficult" aeration points, i.e. 5 and 6.
Vent at vent points 2, 3, 5, 6, 7 and 8.

Aeration 8
Aerate at aeration points 2, 3, 5, 6, 7 and 8.

If the engine does not start, start from the beginning again NOTE, if necessary, include venting point 4.
NOTE Bleed point 1 lets air into the system if it is opened if the tank is lower than the bleed screw. Only
use it if there is a natural drop from the tank to the engine. Note that when you have to release a splash
from the water separator, on some models it may also be necessary to release air screw 1 in order for
anything at all to come out at the bottom via the drain tap.
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2.5.1 Description of the venting points

Bleeding point 1, Pre-filter - extra fuel filter See

picture 2.5. This bleed point should not be used on our engine as we are sucking fuel from the
tank. If this ventilation point is opened, air is let in here instead.
For those who have a tank that sits above and has self-pressure, they can vent here, but
all MD5s have a suction pump, so you should never vent here. On our boat, it only makes sense
to open if the tank is filled to the maximum, i.e. you have self-pressure.

Bleed point 2, Fine filter (Fuel filter)

This is by far the most important aeration point. In many cases, such as when changing
the pre-filter and fine filter, it is enough to air here.

See picture 2.11. Be prepared for fuel spills. Have a rag or paper towel to dry with.

Open the vent screw on the fuel filter about 4 turns with a screwdriver or key if the screw has
been replaced. Pump fuel with the hand pump on the feed pump until air-free fuel comes out.
Then close the vent screw.

NOTE If the pump action is poor, or if the hand pump does not pump out any fuel, turn
the engine's flywheel slightly so that the pump's drive cam changes position. Alternatively,
open the decompression handle and spin the flywheel. You can also drive with the
starter motor, but you should then have two people. Be careful not to get clothes or hair
caught in the flywheel. If the engine were to start and you get stuck, it means danger to
life.

Bleed points 3, 4, 5 and 6 at the injection pump.

Pictures 2.11, 2.14, 2.15 and 2.16 show where ventilation points 3, 4, 5 and 6 are located on
the engine.

Picture 2.14, Aeration point 3, 4, 5 and 6.

The injection pump seen from
the “back.” Bleed point 3 on the
injection pump (left with the large
screwdriver) use a 10 mm wrench Bleed
point 4 (right with the small
screwdriver). Older engines lack venting
point 4. Venting points 5 and 6 are on the
top and hold the pressure pipe that goes
on to the injector.
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Picture 2.16, shows vent point 4 on

another boat's MD5A engine
Picture 2.15, shows the venting point 3
at the injection pump. Use a 10 mm
spanner. Bleed point 4 is hard to find on
our engine.

Vent point 3 and 4 Vent

point 3; Open the bleeder screw on Use a 10mm wrench (block or joint wrench not a
screwdriver), open and hand pump until airless fuel comes out, tighten.
See picture 2.14 and 2.15. You may also need to drive around with the starter motor to get
fuel from the injection pump.

On older MD5A engines there is no recessed air screw to bleed even at bleed point 4.
NOTE: It is impossible to open vent point 4 on our boat, it is stuck.

Vent points 5 and 6.

Only air here if absolutely necessary as it's a bit fiddly to access. See pictures 2.15 and
2.17.
- First loosen the pressure pipe nut (vent point 6) with a 17 mm ring spanner, at the
same time hold with a 19 mm spanner on the lower nut, the pressure
valve closure itself).
- Then loosen the lower nut (pressure valve seal – venting point 5) with
a 19 mm ring spanner.
- Pump in air-free fuel and tighten the lower nut (the pressure valve seal – venting point 5)
with a 19 mm ring spanner, tightening torque 35 – 40 Nm. Now aeration point 5 is
ready.
- Pump in airless fuel again and now tighten the upper pressure pipe nut with a 17 mm
ring spanner. Now aeration point 6 is ready. According to the instruction
manual, venting point 6 is not an "official" venting point.

Note that getting fuel can be a bit fiddly. On our engine, you cannot tighten vent point 5
completely because then the engine will not start. Tighten "just enough" with the 19 mm
wrench. In order to then tighten the pressure pipe nut (ventilation point 6), one must
therefore hold against the pressure valve closure (ventilation point 5) with a 19mm key. Not
simply to explain in text…

It may happen that diesel leaks "under" the pressure valve seal (venting point 5).
There is a small O-ring that seals, see picture 2.20 where you can see the black
rubber ring on #3. If it leaks, disassemble and replace the O-ring, but be extremely careful,
see warning text on the next page.
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Figure 2.17, ventilation points 5 and 6.

Pressure valve seal,
pressure pipe nut 1 and the beginning
of the pressure pipe

NOTE If you loosen the

pressure valve cap completely, a lot
of small stuff can come loose and
disappear behind the engine, so be
careful. Especially the small spring
can bounce off and disappear
under the engine. See picture 2.20.

Bleeding points 7 and 8 at the injector

The next place to vent is on the right just above the air cleaner on the right side of the engine, see
picture 2.18.

Vent point 7.
This is not a venting point according to
the manuals. You can also consider skipping
this airing point. To vent, loosen pressure pipe
nut No. 2 at the end of the pressure pipe and
pump out air-free fuel. Then tighten.

Vent point 8.
Loosen the vent screw on the leak oil pipe
with a 10mm spanner, then pump out air-free
fuel. Then tighten.

The leak oil pipe is a return line for

excess fuel that is routed back to the fine
Picture 2.18, the end of the pressure filter. The connection is on the
pipe, with venting point 7. Venting point 8 is pressure side of the feed pump.
on the leaking oil pipe.
The instruction manual for the MD5C (newer engine than our MD5A) says that you can also bleed
the return line (the oil leak pipe). It is unclear what is meant, it is probably ventilation point 8 that is meant.
But it can also be the other end, i.e. where the leaking oil pipe connects to the pressure side of the feed
pump.

All aired?

Now the engine should start, if not air from the beginning again and don't give up. If air still enters,
replace all fuel system gaskets and replace all fuel lines. Check especially the large gasket by the fine
filter.
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2.6 Injection pump

Injection pump is often also called high-pressure pump. It pumps diesel to the spreader at exactly the right
moment. It is difficult to make and special measuring instruments are needed to set it. There is a Bosch
service almost everywhere in Sweden and you can have the injection pump serviced there.
MD5A and MD5B have the same type of pump but MD5C has a different pump.

2.6.1 Operating principle direct injection Volvo Penta MD1

I have not found any exact description of how the MD5 injection pump works.
But have found a good description for the pump in VP MD1 and the principle also applies to VP MD5.

1. Pressure pipe (outlet to the spreader)

2. Spring 3.
Relief valve 4. Seal 5.
Pump element
6. Sleeve 7. Roller
bumper 8.
Spring 9. Control
rod 10.
Pump housing 11.
Inlet 12. Screw
connection

Image 2.19 Injection pump on the Volvo

Penta MD1 (833740) is similar in function
but not identical to the one on the MD5
(838150)

The injection pump is driven by a cam mounted on the camshaft extension. The pump is of the piston type
and works with a constant stroke. The injection pump consists of a piston and a cylinder, which is closed at
the top by a spring-loaded pressure valve. The pressure pipe is connected to the pressure valve, which
leads the fuel to the injector and spreader.

With the help of the control lever and the control rod, the pump piston can be turned during operation,
whereby the amount of fuel injected by the pump can be changed. For this purpose, the piston is provided
with a slanted lower edge and the injection therefore ends sooner or later depending on the position of
the piston.

In order to cause the rotation of the piston, there is a control sleeve that affects the lower end
of the pump piston. When the piston is turned so far that the vertical milling exposes the inlet channel, no
fuel is injected due to the fact that the fuel is not exposed to any pressure increase.
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The centrifugal governor (English centrifugal governor) is built into the housing at the
injection pump and during operation regulates each set speed within the engine speed range by
changing the amount of fuel injected by the pump. The governor hub, with two centrifugal weights, is mounted
on a shaft driven by the transmission. The centrifugal weights move a sleeve which, through a spring-loaded
lever, affects the injection pump's control rod when the speed increases and decreases, so that when the
speed decreases, it moves in the direction of increased fuel consumption and vice versa. In picture 1.9,
you can see the MD5's regulator hub in the lower part of the exploded view

2.6.2 Injection pump MD5

It is the same type of injection pump in MD5A and MD5B. Note that the MD5C has a different injection pump.

Under the pressure pipe (metal pipe) that leads fuel from the high-pressure pump
(injection pump) is the pressure valve seal (perhaps also called pressure valve screw
connection), see picture 2.17. Under this strong bolt, which you need a 19 mm ring spanner to open, there
are a lot of small mechanical parts that can get loose and you can't start the engine. On our MD5 it seems
to happen sometimes when air gets into the injection pump. First, open the pressure pipe nut (the upper
one) with a 17mm wrench.
If you then loosen the lower part (with a 19 mm key) perhaps one or two turns, you can tap a little gently, if
you're lucky you'll hear it rattle a bit and things fall into place and the engine works again. If that doesn't
help, you can try to take apart and simply put the things back. If you are lucky, the engine will start after
this intervention.

NOTE Be extremely careful if you unscrew the parts. When the pressure pipe nut is completely
loosened (no. 3), the small spring (no. 7) can pop off and it will most certainly end up in a
hidden place under the engine.

On the exploded view, picture 1.8, you can see all the parts of the injection pump.
I lack the exact name of the parts marked with ?.

If you are inside the injection mechanism and mecha, you must keep it clean. There must be no debris
entering the injector.

According to the workshop manual, the injection angle is set by putting different gaskets between the
housing and the engine block. Here I am unsure what applies.
According to the exploded view, it seems as if the thickness of adjusting washer 6 in the injection
should be changed. Does anyone know and can clarify?

NOTE Be very careful if you are going to dismantle the high-pressure pump (injection pump).
Loosen the three hex screws on the top. Then you have to get behind the cover plate for the regulator (see
exploded view 1.9) and loosen a nipple. There is a slight risk of the nipple coming loose and falling into
the oil sump. If it lands on a gear, the engine will break, if it falls to the bottom of the engine, it may remain
in the oil sump. If you are unsure how to do it, let a specialist do the job.
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Picture 2.20, picture of the pressure valve seal on the high-pressure pump and the parts that are "loose". The
numbers show the parts according to the exploded view picture 1.8. NOTE the plug with washer and spring (5, 6
and 7) are the wrong way round in the picture.

Note that parts 5,6 and 7 have been sitting the wrong way around in our engine with the "hat" facing downwards
as shown in picture 2.20. But it must be mounted with the "hat" upwards according to the exploded view picture 1.8.
I have discussed this with Drevia in Lysekil who insists that the "hat" must be facing upwards, but strangely
the engine has worked anyway. They now sit facing the right direction and that works too. I have received a report
from a reader that his engine has also had the "hat" turned the wrong way and that it has worked. Apparently it
doesn't matter which way it is turned.

Picture 2.21, The pressure valve (no. 9) consists of two parts. The left one is inserted into the hole on the right. The
copper gasket seals against the bottom of the spring-loaded plug.
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Picture 2.22, Parts of the pressure valve closure, Plug with washer and spring no. 5, 6 and
7 (the bolt with a spring) is has been sitting this way in our engine which is wrong, but has worked
in any case. The "hat" on the plug must face the other way. Also note the black O ring which
may need to be replaced after a few years.
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2.7 Spreader

The spreaders should be checked at intervals of perhaps 4 - 5 years. I have never changed the distributor
myself and therefore have nothing more to add than what Volvo says. In the fall of 2006, Volvo Penta
changed the distributor in our engine when the old one stopped working.

Tools:
Ring spanner 10 mm for the vent screw on the leak oil pipe and the yoke.
Fixed spanner 17 mm for the pressure pipe nut

Removing an injector is a work operation that requires both great care and accuracy. According
to Volvo Penta's Do-it-yourself handbook, you should start by draining the cooling water to protect yourself
against water intrusion into the engine. Should the distributor sleeve follow up a bit after all, the seals will
loosen and if there is water in the engine, this will flow down into the cylinder. According to Volvo
Penta's mechanics in Västerås, you don't need to drain the water.

Clean thoroughly around the injector. Disassemble the pressure and leak oil pipe from the injector.
See picture 2.18, 2.23, 2.24 and 6.2, be prepared for fuel spillage. Bend the pipe back slightly, if necessary
loosen the pressure pipe a little at the injection pump. Disassemble the spreader yoke. Twist the
injector back and forth a few times to loosen it from the sleeve. Gently pull the injector up while turning it
back and forth.

If the injector is to be submitted for pressure testing, protective caps should be fitted to all
fittings to prevent dirt from entering the fuel system. Before reassembling the injector, it must be sprayed
with anti-rust oil to prevent it from sticking in the sleeve.

Install the yoke. Tighten the nuts to 8 Nm (0.8 kpm), the workshop manual from 1975 says 10 Nm, which
in practice doesn't matter. In the workshop manual from 1998, it says 8 Nm again, so that's what should
apply. Connect the pressure pipe and the leak oil pipe with new gaskets.

Picture 2.23 Dismantling of spreader MD5

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Picture 2.24 Spreader MD5

2. Spreader holder Nozzle holder body

3. Adjusting Adjustment shim
washer 4. Running
Spring 5. Spring Spring disc
plate 6. Intermediate Intermediate piece
piece 7. Guide Guide pin
pin 8. Hole Hollow screw
screw 9. Spreader Nozzle nut
nut 10. Gasket The gasket

11. Spreader Nozzle

Washer No. 3 adjusts the spreader's opening pressure. By changing the washers, which are available in sizes 1 –
1.95 mm in steps of 0.05 mm, the correct injection pressure is set.
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2.8 Refueling of diesel

Make sure to fill the fuel in the right place in the boat. Mixing up the filling holes for water and diesel leads to
disastrous consequences. It is especially difficult if there is water in the diesel tank, then you can't drive
away without stopping. When filling, look at the transparent hoses under the cockpit during refueling. Fill
slowly (very slowly towards the end) so that it does not foam over. Since the summer of 2006, we have only
filled "manually" from 5 liter spare canisters as we think it feels safer.

The modern diesel oil sold in Sweden is so-called environmental diesel (MK1 and MK2) which have lower sulfur
and aromatic content than the "old" diesel. This more environmentally friendly fuel has a lower heat and viscosity.
This results in a reduction in engine power of up to 5 - 10% and an increase in fuel consumption of approx. 3%. In
some cases, the response when applying the gas can also be affected. At increased fuel temperature, these
effects are amplified. Large, full fuel tanks provide cooler fuel, reducing the problem.

You must never fill in the so-called diesel booster, two-stroke oil, old engine oil, etc. in the tank to "lubricate" the
injection. According to Volvo Penta, the service life is shortened.

To avoid the engine drawing air in heavy seas, you should never go
below half a tank. Refuel often to be on the safe side. Bring a spare can
to have ready in case of bad weather. In a full tank, the risk of
condensation is also minimized and thus the so-called "diesel snakes".

2.9 Fuel consumption

Our engine consumes about 1 liter of diesel per hour at about 6 knots in calm weather. At 2000 revolutions
we are usually around 5.8 knots (with the old iron folding 14*6). With the new bronze folding 14*8 we
make 6.0 knots at 2000 revolutions. Top speed with engine for our boat is about 6.6 knots which we have only tried
for a short time. Measurements show that the engine draws exactly 1 liter per hour, i.e. 1 hour of driving = 1 liter
consumption

We once towed a 30-foot sailboat for a few hours and our speed was then 5 knots, the total weight was 6 - 6.5 tons,
and we then consumed about 2 dl per nautical mile.

2.9.1 Theoretical calculation of fuel consumption

A simple rule of thumb is that diesel engines consume 0.17 - 0.23 liters/hp per hour. Higher engine power
results in better efficiency and thus lower consumption.

Another way is to start from another rule of thumb that a diesel engine consumes 200 – 260 g/kWh. I have tried to
reason my way through how to calculate the consumption and here is an attempt.

1 hp = 0.735 kW,
Density diesel: 0.88 kg/l, Density
MK1 Diesel, environmental class 1: 0.815 kg/l (according to OKQ8).
At Swedish supermarkets, only environmental class 1 (so-called environmental diesel) can be refueled.

My practical measurements show that consumption in the lower range, i.e. 200 g/kWh seems to agree fairly well
with our fuel consumption. Volvo Penta specifies a consumption
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292 – 300 g/kWh which may apply if the engine is run at full throttle through all speed registers.
But you don't do that in real life.

Consumption diesel: 0.227 l/kWh = 0.167 l/hp (consumption/density then converted to hp)
Environmental diesel consumption: 0.238 l/kWh = 0.175 l/
hp The above values are obtained by dividing 200g/kWh by the density then multiplying by
0.735 to get litres/hp.

The tables below show theoretical calculations of what an MD5A draws at different speeds.
The tables apply to all types of boats as neither distance nor speed is included. I can state that our
average consumption per hour of about 1 liter matches well. Other values should only be seen as a
guideline as the margin of error is certainly in the region of 5%. The cruising speed for the MD5A is at
2000 rpm, when you are at 80% of the maximum rpm.

Diesel, consumption in litres

Speed hp 5 min 15 min 30 min 45 min 1h 2h 3h 4h 5h 10h 20h
2500 7.5 0.10 0.31 0.63 0.94 1.25 2.51 3.76 5.01 7.52 12.53 25.06 2000 6.1 0.08 0.25 0.51
0.76 1.02 2.04 3.06 4.08 6.11 10.19 20.38 1600 4.4 0.06 0.18 0.37 0.55 0.74 1.47 2.21 2 .94
4.41 7.35 14.70 1200 3.3 0.05 0.14 0.28 0.41 0.55 1.10 1.65 2.21 3.31 5.51 11.03

Figure 2.24 theoretical diesel consumption

Environmental diesel, consumption in litres

Speed hp 5 min 15 min 30 min 45 min 1h 2h 3h 4h 5h 10h 20h
2500 7.5 0.11 0.34 0.68 1.01 1.35 2.71 4.06 5.41 8.12 13.53 27.06 2000 6.1 0.09 0.28 0.55
0.83 1.10 2.20 3.30 4.40 6.60 11.00 22.00 1600 4.4 0.07 0.20 0.40 0.60 0.79 1.59 2.38 3 .17
4.76 7.94 15.87 1200 3.3 0.05 0.15 0.30 0.45 0.60 1.19 1.79 2.38 3.57 5.95 11.90 Image
2.25 theoretical environmental diesel consumption

Energy content of different fuels (kWh/m3)

Diesel MK1 and MK2 9772 kWh/m3 = 9.772 kWh/l
Diesel MK3 9952 kWh/m3 = 9.951 kWh/l
Gasoline 8720 kWh/m3 = 8.720 kWh/l
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Lubrication system, oil in engine and gear

According to all manuals, you should check the oil very often, which in reality you don't do.
It may be advisable to check in advance if you know you will be driving for several hours. Many people think that you
should only check if there is too little oil, but it can actually happen that the oil level increases. If the amount
increases, it is actually diesel that has entered and mixed with the engine oil.

Check the oil in the engine in the usual way by reading on the oil dipstick (the red handle). The level
should be between the two instantiated points.

Even if you drive very little, like only 2 hours, the oil should be changed once a season. The oil absorbs water,
regardless of whether you are driving or not. If you drive your engine a lot, the water evaporates, if you drive a little,
the water remains, which can then condense in the engine. If condensation forms on the cylinder walls, there
is a risk of engine damage. Corrosion (rust attack) causes poor compression in the cylinder. If you drive a little,
the risk increases and therefore it is necessary to change the oil even if you have barely driven the engine
during the season.

Diesel contains small amounts of sulphur, and therefore the lubricating oil contains additives that counteract
the formation of sulfuric acid. If you drive a lot, you may end up with a little sulfuric acid forming over time,
which can also cause corrosion. If you drive a lot, it is therefore necessary to change the oil.

Whether you drive a little or a lot, the oil should be changed at least once per season.

Even if the oil looks fine in the gear, there may be small amounts of water. The cost of 1.8 liters of oil in the gear
is negligible and must be changed once a year whether you drive or not.

If you get an unusually high oil consumption at the beginning of the season, it can easily be the case that there is
water in the oil that evaporates. If the oil is also diluted by fuel, it can be an incredible amount of oil consumption.
It's just a matter of filling in new oil, or simply changing both oil and filter.

It doesn't matter if the engine consumes a little oil, on the other hand, if you notice that the level is increasing, i.e.
diesel is coming in, then you have to be careful not to overfill so that the engine can start running on the
lubricating oil and rushes uncontrollably. If this happens, stop the engine immediately with the compression handle. If
you happen to have an MD5 without a decompression handle, you must risk your life to throttle the air intake.
Watch out for the flywheel, if you get stuck there is a risk of life-threatening injuries. After that, the oil
should be changed, if this is not possible, reduce the amount of "oil" before starting the engine again, drive very
carefully.

3.1 Oil change in the engine

Engine oil must be changed after 50 hours of operation or once per season.
Oil filters must be changed after 100 hours of operation or once per season.
Pump out the oil with a separate hand pump. Collect the waste oil in a container.

2.0 liters of oil excluding the oil filter 2.1

liters of oil including the amount in the oil filter.
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are good reasons to check the oil often. Cooling water (greyish milky oil) can enter if there is a
leak around the water pump and diesel oil can enter from the feed pump (fuel pump).

Always carry a splash of spare oil in the boat. Volvo Penta prescribes SAE 10W/30 CD oil.
You can therefore buy today's cheapest standard oil such as Biltema's mineral oil SAE 10W/30 as it
fully meets the requirements. NOTE Modern synthetic or semi-synthetic oils must not
be used.

It's messy, so clear away textiles (carpets, cushions, etc.) and have rags ready. Run the engine for 15 – 20
minutes, let it come up to operating temperature so that the oil is fluid. Turn of the engine. Wait
a few minutes so that as much oil as possible flows down to the "bottom" of the engine. Pull out the dipstick,
insert the oil bilge pump into the hole and pump out the old oil. We use a vacuum pump (so-called vacuum
suction) in our boat. Use vessels with a volume indication so that you know how much oil you get out of the
engine. Slag collects at the bottom, so try to suck out as much as possible. It is difficult to get more than 1.5
liters out. Change the oil filter (during winter storage or after 100 operating hours). Have a cloth
ready.

Put a little oil on the rubber ring of the new filter and tighten by hand. When you feel resistance, pull one
more turn, do not use tools. Fill with new oil in the opening for oil. Remember that there is always some
old oil left, so do not fill in the maximum amount as stated in the manual.
Allow the oil to sink for a few minutes and check with the dipstick before starting the engine.
Then start the engine and let it run for a few minutes so that the new oil can circulate in the engine.
Check that the new filter is tight. Stop the engine and check the oil again after a few minutes.

Some boat owners change the oil twice with a warm run in between to really get as much old oil out as
possible. If you are extremely careful, you also change the filter between changes, you can use a
cheap Biltema filter for about SEK 50 for the intermediate change.

3.2 Oil change in the 110S gear

There is also an oil dipstick on the drive. The dipstick is fitted with a bayonet mount, which is why it
must be turned to be lifted and put back. Note the sealing ring on the stick. When measuring, the
needle must be turned to the locked position.

Filling takes place through the dipstick hole. NOTE: Do not overfill. The gear oil must be changed once per
season and this can only be done when the boat is on land. It is the same type of oil in engine and drive.
The oil quantity is 1.8 litres.

Gear oil must absolutely not be used, the drive will be destroyed. Always use the same oil as for
the engine.

3.3 Oil pressure

The sensor for the oil pressure is on the front side of the cylinder head, see picture 5.3. When
starting, the oil pressure light should light up and the buzzer should sound. Once the engine has started,
it should shut off after a few seconds. On our engine it howls for 4 - 5 seconds until the pressure has built up.

If the oil pressure drops, the engine must be stopped immediately. First check the oil and top up if necessary.
If there is a lot of engine oil under the engine, it has leaked. Check the gaskets at the filter, oil
dipstick and oil filler hole.
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It may happen that it is the sensor itself that has broken and in that case it must of course be replaced.
You can test by unscrewing the sensor, putting your thumb there and feeling if there is reasonable pressure
and then it is simply the sensor that is broken. Of course, you can also connect an oil pressure gauge, or
you can buy a new sensor and try it. The sensor is actually quite cheap (about 150:-) so buy a new
one if you suspect a fault. If the fault persists after replacing the sensor, it must be a fault with the
mechanical oil pump, which is unusual and means a lot of work in taking the whole engine apart.

If you want to install a measuring instrument to measure the oil pressure, you have to change the sensor.
The threads for the oil pressure sensor are 1/8" NPTF (National Pile Thread Fuel which is an
American standard for pipe threads) which is a common dimension for oil pressure sensors on combustion
engines.

3.4 Oil leakage

Old engines almost always leak some black engine oil, which is harmless as long as you keep it all under
control by keeping an eye on the oil level in the engine.

A common place where oil leaks from is the valve cover gasket. Replace gasket if leaking. If that
doesn't help, tighten the screws on the valve cover a little more. If still leaking, check the gasket at the
dipstick and at the oil filler cap.

Other possible sources of error are the oil filter and the attachment of the feed pump (fuel pump) to
the engine block.

Then it can leak from another gasket in the engine, but to fix this you have to take the engine out, which
is hardly worth the trouble. A small drop of oil is usually completely harmless.
There is a little oil dripping from our engine. If we drive for a few hours, we find a small black spot the
next day under the engine. It is only a few ml and is completely harmless.
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The electrical system

Separate drawing shows how the electrical system is built on the NF 351. Basically everything is
new and replaced before the electrical center. It is important to have proper cables from the generator
to avoid voltage drops. To avoid voltage drops, also run a strong cable ("ground") from the
batteries to the generator. We use Biltema's recreational batteries which fit very well in the space we
have available. Of course, you can use other types of batteries.

When the key is turned, the red oil pressure light and orange charge light should light up at the same
time as the buzzer sounds. The red temperature light does not light up because the engine is cold.
It's a bit silly because you can never check that the lamp is working. You can check by holding a
cable against the cable lug on the temperature sensor.

The engine panel on our boat has a special extra function. There is a small rocker switch located aft
(pictures 4.1 and 4.2) which can be switched off (up) when starting a cold engine.
When the motor runs smoothly after a few minutes, turn on the power by flipping the switch down.
What happens now is that magnetizing current is supplied to the generator so that it can begin to
charge. Once charging has started, the generator charges regardless of how you then change switch
1. But to receive an alarm if the generator suddenly stops charging, you must have the switch turned on
(position down). If the charging warning light comes on when you tilt down immediately after
starting (the orange light on the right), the generator is not charging yet. To remedy this, you then
have to apply a little more gas to start charging. The MD5A gives a moderate 7.5 hp, the new
generator takes about 1 hp if the batteries are empty, so to simplify when starting a cold
engine, you can wait a few minutes to start charging to avoid engine stoppage in the middle of a
crowded port.

When the charging light has gone out, you can check that the voltmeter at the electrical panel
shows that the voltage is in the range of 13 – 14.4 Volts (depends a little on rpm and how discharged
the batteries are).

The normal position is that the power switch is tilted downwards (on) when driving. You then receive
an alarm if charging stops. If the power switch is off, no charging alarm will appear on the panel.
As soon as the generator has started charging, it does not need an external
magnetizing current as it "charges anyway", the whole thing becomes like a "self-playing piano".

If the orange charging warning light suddenly lights up and the buzzer sounds, it means the generator
has stopped charging. You can drive on knowing that you are saving power in the batteries.
Nothing can really be damaged on the engine or generator. It is harmless to remove the key while
the engine is running or to break the main engine switch on our boat.
On our boat, the engine breaker cuts power to the starter motor and control panel. However, one must
realize that no engine monitoring is activated, which can cause engine damage if it overheats or the oil
pressure drops. Some boat owners apparently have the cable from the generator to the battery
through the switch, which is objectionable because the charge controller can be damaged if the
engine's main switch is closed.
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If the red temperature or oil pressure warning lights illuminate on the control panel and an
audible signal sounds, the engine must be stopped immediately and troubleshooting begun.

Brief description: - On
start rocker switch up (off)
- When the engine runs smoothly, flip the power switch down so that charging
begins - To have monitoring activated by oil pressure, temp and charging, do not
cut off the power with the key or the main engine switch.

If in certain situations you need all the power to the propeller, you can interrupt the
charging by stopping the engine. Reboot with the rocker switch up. Then run without
dragging start the charge, i.e. always in up position. The generator will not charge and the
maximum possible power will therefore go to the propeller.

Our engine panel is refurbished. I have bought new lamp holders and a rocker switch at Bil &
Båt El in Västerås. Spare lamp for the panel is type Philips 12V 1.2W W2x4.6d, see picture 4.3. A
cheap tachometer from Biltema has been fitted. Costs SEK 198 to compare with VDO's tachometer
which costs about SEK 1000. It is likely that the cheap tachometer does not withstand moisture
as well or something will rust. Volvo Penta's original lamps are 2 W.

Picture 4.1 renovated engine panel in the cockpit with "tread protection", new lamp holders,
new rocker switch to control the magnetizing current. If you are not sure how to behave with the
rocker switch, leave it as in the picture (down) and the generator will always charge.
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Picture 4.2, engine panel in the cockpit, The new rocker switch is in "position 5".

Picture 4.3, Packaging for spare lamps, sold individually by Bil & Båt El

4.1 Emergency start of the engine

If the engine is completely silent when trying to start, check the

following: - That the main switch for the engine is switched on.
- Is there voltage in the starter battery?
- Check if the starter relay "clicks" at the starter motor when the starter key is turned. If not, there is a fault
with the "control current". o There is a
slight chance that the key has caught itself so that the white wire has no voltage. This cable provides
operating current to the relay on the starter motor. You can then unscrew the
motor panel (4 star screws) and measure with a measuring instrument. See further down
in the text how to make a "stealth connection".

o If it turns out that there is voltage coming out of the key connection, then the fault must be at the
other end. Most likely, the white cable's cable lug has come loose at the starter motor.
First disconnect the power to the motor to avoid shorting the electrical system. Check that
the white cable is correctly mounted. See picture 4.4.
o Fault on the relay in the starter motor, contact Volvo Penta.
- Otherwise, there is probably a fault with the starter motor, contact Volvo Penta. Replacement starter motors
are expensive but you really have no choice.

If in an emergency it is necessary to start the engine, the power can be switched temporarily. Be careful
as a short circuit can be fatal.
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4.1.1 When the starter battery is empty

- If the starter battery is empty, you can quite brazenly charge it up with power from
the consumer batteries via switching (difficult) or via a starter cable, which is significantly easier as only
the + conductor needs to be connected (the – poles are already connected). The current now "rushes" to
the starter battery and it sparks a little on the pole clamps. The disadvantage of this method
is that you run the risk of destroying your consumable batteries and then you end up with all the batteries
completely exhausted.
- The better option is to disconnect the engine power knob so that the starter battery is disconnected.
Then connect a starter cable from the + terminal of the consumable batteries to the fuse holder
for the starter motor (red located in the engine compartment).

- MAKE SURE THAT THE STARTER CABLE'S + CONNECTION CANNOT SHAKE OFF AND
FALL DOWN TOWARDS THE ENGINE AS THERE WILL BE A SHORT CIRCUIT WITH IT
RISK OF BATTERY EXPLOSION - DANGER TO LIFE
- The control panel now receives power so you can start via the key. Make sure the charge
is switched off (opened power switch on the control panel).
- When the engine has started: o
Immediately disconnect the starter cable, then the main switch for the engine
turned on.
o Turn the power switch (down) on the control panel to start charging
all batteries.
o Now run the engine for an hour or so to recharge the batteries. If the error persists at the next start,
the starter battery must be replaced as soon as possible.

4.1.2 If the key at the control panel is faulty It may happen

that the key is accidentally kicked, or that the switch is simply faulty. To start, you then have to "sneak" your way
past the key. NOTE If you have fresh water cooling, you must ensure that the electric water pump is engaged otherwise
the engine will overheat.

Alt 1. Unscrew the motor panel and disconnect the white cable towards a live point. The
starter motor will cycle and probably start.
Alt 2. See picture 4.4. Connect a wire directly from the battery to the pin on the starter for the white
wire. First connect the cable to the starter motor. Hold the other end gently against the + terminal
of a battery. The engine will then probably start immediately. WARNING DANGER TO LIFE - THINK
ABOUT WHAT YOU ARE DOING, NO ARMS, LONG CLOTHES OR LONG HAIR INSIDE THE
ENGINE WHEN JOGGING.

4.1.3 If the starter batteries are almost empty You

must be two people.
You can try to use the same method as when cranking the engine by hand.
Note that the model with S-drive does not have a hand crank.
The trick is for one person to "open" the engine with the decompression handle. When the starter gets the engine
spinning, you turn the handle back so that compression occurs. With a bit of luck, you can then start the engine.
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with the boat neighbor's battery, when all own batteries are discharged.
- Disconnect the motor current
- Connect the neighbor's battery using the starter cables (+ the pole can be connected to).
the fuse holder in the engine compartment. – pole towards the motor or a black terminal block.
The boat neighbor should run his engine at a relatively high speed so that his generator is charging
at the same time as starting attempts are made. I guarantee that we will not charge our batteries with the
boat neighbor's power if you follow my step-by-step description.
- Once the engine has started: o
Immediately disconnect the starter cable, always starting with the black cable. o Turn on
the main engine switch. o Flip down the power
switch on the control panel to start charging. o Run the engine for an hour or so to recharge
the batteries. If the error persists at
next start, the starter battery must be replaced as soon as possible.
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Alternator and starter motor

Figure 4.4, electrical connections on the starter motor.
The strong black cable in the middle (which goes
straight up) is secured with a 400A fuse. The
narrower red cable goes on to the fuses on the
engine (by the feed pump) and then on to the
engine panel in the cockpit. The white
cable (with red and black markings) comes
from the "key" on the engine panel and causes
the starter relay to turn on the
power from the heavy duty cable. It has happened
that the white cable has jumped out. Make
sure it lands on the correct pin. In the picture, the
white cable hangs loose and must be mounted
on its pin.

It has happened that the cable lug with the cable for
the magnetizing current has become detached from
the generator. It is the black cable coming from the
control panel. It sits on a "split" cable lug with the
cable that senses the charge level on the
charge distributor (that cable is also
black). See picture 4.5.

We have connected a tachometer to pin W.

Green cable that goes to the engine panel. Our new
generator provides 70A. It sits mounted on
two new metal brackets to match. When replacing
the generator belt, a belt with a dimension of 1350
mm must be used * 9.5
mm is mounted in our boat. For the standard
generator, a shorter belt 1300 9.5 mm is used.
*
etc
Figure 4.5, generator.

The generator is made by Valeo When starting from cold, it is advantageous to

On the generator plate it says: wait a few minutes before starting the charge until
Valeo the engine runs smoothly. The reason is that a 70A
9AR2712P generator consumes approx. 1 - 2 hp of
14V 70A the engine's total output of 7.5 hp.

Always bring an extra generator belt in the boat.

Original generator (Marchal) has no connection for tachometer, there is a conversion kit to buy
for just over SEK 1200. But then it is better to buy a new generator instead. Note that the fuse holder on the engine
block is bolted according to picture 4.6. On the back is a bolt that is tightened with a 13 mm spanner.
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Picture 4.6, Allen key on the front and 13mm fixed key on the back.

4.4 Batteries

4.4.1 State of charge of the batteries

When the current from the generator is high, in our boat max 70 A, the battery is very discharged.
The generator runs very heavy. The voltage is low (13.2 – 13.8 V). When the battery has reached approx.
85% of its capacity, the charging process slows down and the charging current drops to perhaps approx.
10A. When the battery is full , hydrogen gas is formed , the voltage is then 14.4 V.
The battery can hardly receive any current at all.

13.2 – 13.8 V The battery is "hungry" and receives a lot of charge The
> 14V battery is starting to fill and can only receive a little charge.
14.4V The battery is full and "eats", hydrogen gas is formed.

4.4.2 The resting voltage of the batteries

In this mode, the battery rests. No charging, no consumption.

12.7 V Fully charged 12.3
V Half capacity 12.0 V 1/3
remaining, must be charged immediately 11.7 Empty, may
be destroyed

4.4.3 Consumption voltage of the batteries

In this mode, you have an even consumption, usually when the boat is in port and has healthy batteries
11.5 – 12 V. If the voltage drops below 11 V with even consumption, you must not draw more current
without adding charging. At 10.5 V, the batteries can be permanently weakened.

12.5 V All good

11.5 V Low capacity or high consumption 10.5
Dangerously low or very high consumption
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Battery types

To start an MD5 engine, you need a battery that can provide at least 75 A at the moment of
starting. The starter motor is 800 W, so a small motorcycle battery is actually enough as
a starter battery.

It is not entirely easy to obtain information about the capacity of the battery at maximum current draw.
Exide (Tudor) says that most of their motorcycle batteries provide 50 – 70 A. I checked with Biltema in
Västerås and there I concluded that all SMF batteries with a capacity of at least 9 Ah are able to
provide enough starting current. So those who want to save space and space can choose a small
battery of 3 - 4 kg.
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cooling system

The engine must be cooled to operate. The MD5, like all other marine engines, is water-cooled.
The cooling water intake is via a tap on the S drive. The water is sucked in by the seawater pump
with the help of the impeller. The water is pushed on to the vacuum valve (siphon switch) and into
the motor itself. The water is distributed at the thermostat housing. The cold water pushes in the lower
right pipe into the engine to cool the cylinders. When the water has been heated up, the thermostat
releases cooling water back to the thermostat housing and on to the upper right pipe and on to the
exhaust pipe to now cool the exhaust gases and is washed out at the "exhaust pipe".

5.1 Overheating of the engine.

If the temp warning indicates overheating, the engine must be shut down immediately. But before
you switch off, check quickly if water comes out with the exhaust gases.
If no water comes out, it is probably the impeller that is damaged. If water comes out, it could be the
thermostat, the thermostat housing, or some cooling duct inside the engine could be clogged.

It happens that MD5 experiences "inexplicable" overheating, but in many cases this can be fixed.

If you suffer from inexplicable overheating, it may be due to a defective thermostat housing. It may
also be because over the years, debris has accumulated in the deepest part inside the engine's cooling
system, i.e. the area inside the drain cock.

If the engine has clogged cooling ducts and you go to Volvo Penta, they will recommend picking out the
engine, removing the top, knocking out the cylinder liner and cleaning the ducts. This is of course the
best method, but it will be expensive, perhaps even prohibitively expensive.

You can, before starting to tear down the engine, try to clean as much as possible. Unscrew the entire
drain cock on the right side of the engine and try to clean it with, for example, a nail as best you can. If
there is no water, rust particles have collected inside and are clogging.

I myself have managed to poke the hole open with a few nails before a black wrasse came out with a
big slurp.

Another MD5 owner has reported that he has cleaned the cooling system without removing the top.
He took a piece of wire connected to a drilling machine. The wire was pryed in through the hole
where the drain cock sits while it was driven around by the drill. He then put a hose on a threaded hose
nipple in the hole for the drain cock and then the impeller had to pump out a lot of goo. This was
repeated a number of times. But it wasn't quite enough, so he also removed the thermostat housing and
pryed his way into and down the cylinder ducts. He was then able to blow into the pipe that leads into the
cylinder head to feel if it is free flowing and after cleaning it was easy to blow..He was advised not to put
the water line hose and flush the block with it, as apparently you can destroy the o-rings that seals
the cylinder liner. Then it was just a matter of screwing together the thermostat housing with its
three pipes and screwing back the brass valve and driving. He is thinking of putting a ball valve with
a hose nipple there to easily empty water into a vessel. So the recommendation is to once in a while
make sure that it is possible to drain the engine of water in order to get all the rust particles out at the same
time.
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The thermostat housing fulfills a very important function for the flow of cooling water. This is how the
thermostat housing works. The cooling water is pushed "straight through" the thermostat housing and
further into the metal pipe that goes into the cylinder head to cool the engine. Some of the water goes
directly through the small hole and out to the exhaust manifold. The thermostat senses the water
temperature in the engine and releases hot water back to the thermostat housing. The hot water
mixes with the cold water that came through the small hole and everything is led away to the
exhaust manifold and cools the hot exhaust gases. The bad hole in the thermostat housing can rust
over time and then get bigger and bigger. If the hole gets too big, too much water is forced
through and then you don't get enough water through into the engine. Most of the cooling water
will then go directly to the exhaust manifold and the engine may overheat. Changing the thermostat
will not help in this situation. It is possible to remove the thermostat in an emergency.

After 29 seasons in the water (1978 – 2006) with seawater cooling, most of the time in the Baltic Sea,
a new thermostat cover was fitted in the spring of 2007 to our engine. The old cover was rusted
and needed to be replaced. On our new thermostat cover, which was installed in the spring of
2007, the hole is measured at 5.6 mm. A thermostat housing lasts maybe 20 - 30 years, then it has
rusted and must be replaced.

You can also try to repair, there are those who have put a Danish 1-krona with epoxy and drill a hole.

Picture 5.1, New thermostat housing, the

small hole is 5.6mm. On an old cover, the
hole can be so large (corroded) that almost
no water is forced into the engine, but
everything is led directly to the exhaust stack.
The brass part has been moved from
the old cover and shines after polishing.
Put new rubber gaskets for the metal pipes.

.
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Picture 5.2, New thermostat housing on our MD5A, the thermostat is located under the cover.
You can see the inlet of cooling water (top left), the passage and further into the cylinder
head (bottom right) and finally the pipe that leads the water on to the exhaust manifold (top right).

If you have fresh water cooling, an internal cooling system is added which includes a
heat exchanger and an electric water pump. It must be ensured that the electric water
rag always works. I do not describe the fresh water cooling system but refer to Volvo Penta
and Martec.

5.2 Thermostat

Thermostat with gasket VP article number 838286-3.

Some rubber sealing rings may be needed for the metal pipes, one for each metal pipe located in
the thermostat housing, item number 829714-5

To open the thermostat housing cover to access the thermostat, a 6mm hex key is
needed.

Always bring an extra thermostat in the boat. In an emergency, you should be able to
remove a defective thermostat. The motor then receives constant full cooling and will
run "cold", which causes the power to drop. There is a risk of water leaking when
the gasket is on the thermostat.

The thermostat in boats with seawater cooling starts to open at 60 degrees and is fully open at
about 75 degrees.
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Figure 5.3, The thermostat is located under the cover (thermostat housing cover). In the picture you can
see the old, now replaced thermostat cover.
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Disassemble the thermostat

Close the cooling water tap on the drive if

the boat is in the water, otherwise there is a
risk of the boat filling with water.

Dismantle the thermostat housing cover and

remove the thermostat. The metal pipes that
are in the thermostat housing cover
have rubber seals like "thick o-rings" and can be
pryed off so that the cover can be removed to
access the thermostat. See picture 5.2, 5.3 and
5.4. You have to detach the cooling water inlet
pipe and also detach the pipe to the
exhaust pipe. Then it is usually easy to get the
thermostat out. To loosen the pipe on the
exhaust bend, 12 keys are needed. Figure 5.4, dismantling the thermostat

Install the thermostat

The gasket sits directly on the thermostat. Start the engine and check that everything
Connect all cooling water lines and make sure it seems tight.
seems tight. If necessary, replace the O-rings for
the pipes. If you are careless with the
rubber seals, there will be a water fountain from the
thermostat cover when you start.
Open the cooling water tap on the drive if the
I think it is easiest to mount in this order: - tap was closed during disassembly.
Lower right pipe
that goes under the frost plug.

- Screw on the thermostat cover

the motor (hex key).
- Insert the pipe that goes to
the exhaust bend, fit the two bolts
on the bend (12mm wrench)
- Mount the inlet pipe (upper left).
Figure 5.5, installation of the thermostat
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5.3 Seawater pump, replacement of impeller

Volvo Penta recommends replacing the impeller every two years. Always carry at least
one spare impeller in the boat.

Impeller kit including gasket for cover, article number 875583-7 Repair kit
containing i.a. Sealing rings, shaft, cam gasket, etc. article number 875584-5. It may be good to know
that the MD5, MD6A, MD7 and MD11 share the same impeller and repair kit. The same impeller is
also in 2001, 2002 and 2003, I don't know how it is with any repair kit.

The impeller pumps cooling water through the engine's cooling system. It is very important to
ensure that the impeller is in good condition. Rubber ages and becomes hard. An old impeller is
therefore not as efficient as a new one. In the fall of 2005, I installed so-called "pin-wings", to facilitate
the disassembly and assembly of the impeller cover. It is extremely much easier to put on
gaskets and lids with pin wings, strongly recommended. To work with the seawater
pump, you need a good pair of screwdrivers with a width of about 7mm.

Picture 5.6, behind the cover's 4 screws is the impeller. The water pump sits awkwardly on
the back of the engine. To simplify replacement, you can advantageously mount so-called "Pin
Wings", which simplifies both assembly and disassembly.

Picture 5.7, behind the cover is the impeller. Our engine now has so-called "Pin Wings" with wing
nuts that make it much easier to access when working on the water pump.
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The impeller cannot stand running without water. Never test-start the engine on land with the
impeller mounted without water being connected to the pump as the impeller will be damaged. There
is a risk of pieces entering the cooling channels, which means problems. If the impeller is
damaged, a possible cause of excessive engine temperature, it must be replaced. If the boat
is in the lake and the water pump is below the surface of the water, the tap for the cooling water
intake on the drive must first be closed before the cover of the pump is removed. Otherwise
you risk filling the boat with water. Do not forget to open the tap again after the work is finished.

To maintain the resilience of the impeller, it can be removed from the engine during the winter months.
Note that this is done after the canning. Rinse the impeller clean in fresh water and store it in the dark in a
sealed plastic bag during the winter months. According to Volvo Penta, you may only lubricate it with
glycerin. Glycerin can be bought at e.g. Apoteket where it is sold under the name Glycerol.

You can easily run the engine for 30 - 60 seconds without an impeller and thus without cooling water
if you are careful. But there will be diesel exhaust "backwards" if you don't put the cap on.

Loosen the cover by unscrewing the 4 screws (or wing nuts). Pull out the shaft with the impeller 10 – 15
mm, or so far that you can unscrew the lead screw.
See images 5.7 and 5.8. Then loosen the lead screw, which is "screwed" across the impeller and shaft. It
is important that the shaft does not come out any further, so hold against the shaft and pull off the impeller
(impeller), see picture 5.10. Try to take it out with your hands. If that doesn't work, use polygrip or a pair of
screwdrivers. However, use tools with care so as not to damage the impeller or pump.

When you buy Volvo's original impeller, you can look at the package's code. If it says 7A, it means that it was
manufactured in January 2007. If it says 8L, it means 2008 December.

According to a rumor, Volvo has had deplorable quality on its impellers for a few years. This has apparently
been fixed since the spring of 2007.

According to the Volvo Penta mechanics in Västerås, there is no problem with pulling out the impeller
while sitting on the shaft. They use two screwdrivers and pry it out. It is so much easier to change if you
pull out the entire shaft. Just push it in, it should be easy. You just have to be a little careful when putting it
back so you don't damage the seals inside the engine. You risk getting water into the engine oil, which
can be devastating. Check the oil carefully after starting so that it seems tight.
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Picture 5.10, shows that you have to hold back so

that the shaft does not come out while unscrewing
the driver shaft.

- Clean the inside of the pump housing and

Picture 5.8, the impeller is pulled out 10 – 15 mm. scrape off the residue from the gasket.
Put some silver tape on the tip of the chisels so that
the impeller is not damaged. - Hold the impeller in your hand and screw in
the lead screw a few turns.

- Now press the impeller onto the shaft as far as the

screw can be screwed into the shaft.
Screw on.

- Install the cover with a new gasket.

According to the instruction manual, the pump

must be dismantled if the shaft comes out. But
according to VP in Västerås, it is significantly
easier to change if you pull out the axle
completely before changing. They do that and
Figure 5.9, shows the lead screw screwed across the it works. That's why I do the same.
impeller and shaft.

There is an accessory for impeller replacements

in inaccessible and dark engine recesses, It is a
puller marketed by Martec called the Impuller. The
impeller works in much the same way as a
corkscrew. The puller grips the impeller core and
by simply rotating the handle clockwise, the
impeller is "screwed" out of the pump.
According to the Volvo Penta mechanics in
Västerås, this is an unnecessary accessory.
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5.4 Vacuum valve

The vacuum valve is a notorious source of water dripping and you can never be sure that it is working.
If it is tight and does not drip, you can never really be sure that the lever action is broken when the
engine is switched off.

The task of the vacuum valve is to prevent negative pressure from forming in the engine (when it is
switched off) which can draw in water through the siphoning action. One will possibly fill the
exhaust system first without the vacuum valve. When the exhaust system is full, it reaches up to the
upper part of the exhaust bend, then the water can flow back into the cylinder if the exhaust
valve is open. Engine failure can occur if you try to start the engine with a water-filled cylinder. Now,
there is perhaps no greater danger with a single-cylinder engine because the starter motor probably
does not have the strength to pull the engine around. But if you have several cylinders, you can
actually bend the connecting rod if it ignites on a cylinder that is not filled with water, total failure is a fact.

There is a way to ensure the function that we have used in our boat. Remove the small rubber
membrane, then thread a small thin 5mm (approx. 10 cm long) plastic tube onto the small metal bend.
The thin hose is in turn inserted into a thicker plastic hose which goes on to a plastic can which
collects the water which is now continuously flowing. The can must be emptied from time to time.
We can drive a couple of hours between emptyings. When the engine is switched off, air is
introduced through the thin hose. You can hear a small "slurp" and thus the lever action is broken
and you do not risk filling the engine with water.

Some boat owners lead the water to a self-bilge or, but I think it's better to avoid drilling holes and
then have to empty the tank at regular intervals.

Picture 5.11, "rebuilt" vacuum valve in NF SWE 351

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If you still want to keep the small membrane,

Volvo says you should do it like this:

Dismantling

See picture 5.12.

Disconnect the hoses from the valve.
Disassemble the valve from the bulkhead.
Hold it upside down and unscrew the nut. Be
careful not to drop the small diaphragm
(1) and gasket (2). Figure 5.12, vacuum valve disassembly

Cleaning
See picture 5.13.
Clean the parts in fresh water so that
any salt deposits disappear.

Figure 5.13, cleaning vacuum valve

Mounting

See picture 5.14.

Hold the valve nut upside down, insert a new
diaphragm and then the gasket.

Also turn the valve upside down and

screw on the nut. NOTE Tighten carefully,
only 2 Nm. If the nut is tightened more, there
is a risk that the valve will not work. Figure 5.14, mounting membrane and
Test the valve by sucking air through the gasket
hole (pipe on later designs) in the nut.
Refit the vacuum valve on the bulkhead and
connect the hoses. Tighten the
hose clamps.
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5.5 The engine as an emergency pump

If you suffer from severe leaks in the boat, you can actually use your engine to pump out
the water. Now it is important to act quickly before the engine gets too much water on it.

1. Call for help immediately.

2. Close the tap for the water intake.
3. If you have an extra hose with you, but loosen the black hose
suction side of the water pump. If you don't have an extra hose, detach the hose at the
water intake.
4. Insert the hose into the water to be pumped away.
5. Make sure the air intake and starter motor on the motor are above the water surface. You
may have to unscrew the air cleaner and turn it over. If water enters the engine through the
air intake, it will stop.
6. Start the engine, check that it sucks as it should, set the speed to maximum to pump as much
as possible.
7. Remember that the engine needs the water for its cooling. Adapt the motor's suction power to
the water inflow. If you are forced to pump for many hours, you may need to top up with more
diesel from the reserve tank.

Bring an extra hose to put on the suction side of the impeller pump. You can have the same hose
as when you preserve the engine in the fall. Just make sure that no debris gets into the hose
that could destroy the impeller or clog the cooling channels. You can possibly put on a sock as a filter
if nothing else is at hand. As long as the engine can be run, you have a helper who can pump for
many hours.
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cover

The following details must be new when the cylinder head is fitted:
Exhaust elbow gasket 803374-8 (same as MD7, MD11 and MD17)
Cylinder head gasket 838127-9
Valve cover gasket 838066-9

The following tools are needed:

Replacing the cylinder head gasket

Allen key 5, 6 mm
Ring spanner ½”, 7, 10, 13 15 and 17 mm Open spanner 17, 18 mm

Socket wrench 10, 15 mm

Control pulling of the cylinder head

Allen key 5 mm for the valve cover
Ring spanner 10 mm for the cooling water connection on the exhaust manifold
Torque wrench with 15 mm socket

Valve clearance adjustment

Allen key 5 mm
Ring spanner 13mm (should actually be ½")
Blade dimensions

Short chisel

6.1 Replacing the cylinder head gasket

Since I haven't done this work myself, I can't give any DIY tips of my own, but all the info comes from VP
books. Cylinder head is the same as cylinder head.

Drain the cooling water from the engine. If the boat is in the lake, the cooling water tap on the drive must be closed.

Close the engine switch Clean the

engine to avoid the risk of dirt falling into the cylinders and valve mechanism.

Disassemble the air filter. Disassemble the exhaust bend. Detach the cooling water line connected to the cylinder
block. See picture 6.1. The exhaust hose does not need to be dismantled from the exhaust bend.

Figure 6.1, dismantle the exhaust bend. For the cooling water, dismantle the two bolts directly against the bend.
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Detach the pressure pipe and the return line from the injector, see e.g. picture 2.17. If possible, put protection on
pipes and injectors. See picture 6.2

Figure 6.2, disassemble the pressure pipe from the injector

Disconnect the cable from the temperature sensor at the rear of the cylinder block (yellow cable) and the cable for
the oil pressure sensor (brown) at the thermostat housing. Then loosen the valve bridge. See picture 6.3.

Figure 6.3.

Lift up the pushrods of the valve lifters. Pull carefully so that the valve lifter arm does not follow.
There is then a risk that this will suddenly release and fall back into the wrong position. See picture 6.4.

Figure 6.4.

Loosen the cylinder head nuts and save the nuts and washers. Lift off the cylinder cover.
Discard the old cylinder head gasket and exhaust pipe gasket. Clean the sealing surfaces on the cylinder
block and cylinder head. Check that the valve lifters are in position above the camshaft. Put a new cylinder head
gasket on the cylinder head and put the cylinder head on, see picture 6.5.

Figure 6.5, fit new gaskets

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Place the washers on the cylinder head studs. Screw on the nuts and pull them loose. Insert the
screws for the exhaust pipe and tighten. The cylinder head nuts must be tightened according to
the tightening schedule in 3 stages with a 15 mm spanner, see picture 6.6.
- 1: 10 Nm, 1 kpm
- 2: 40 Nm, 4 kpm
- 3: 70 Nm, 7 kpm

Figure 6.6, tightening schedule

Install the push rods. Install the valve bridge. During tightening, check that the ball on the
adjustment screws of the rocker arms is in the ball cups of the push rods. See picture 6.7.
Install the sensor cables for temperature and oil pressure.

Figure 6.7

An absolutely necessary action now is to check and adjust the valve clearance. See the "Valve
Adjustment" section.
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6.2 Control tightening of cylinder head nuts

The cylinder head nuts must be checked with a cold engine. After the test pull, you have to refit the
valve cover and warm up the engine so that you can check the valves.

Start by opening the valve cover, see chapter 6.3. The cylinder head nuts (top cap nuts) must be
retightened every 100 operating hours. The reason is that cast iron stoppers can easily settle a little so
that there are leaks with breakdown as a result. Use a torque wrench and tighten to 70 Nm (7 kpm)
according to the tightening schedule in picture 6.6. Note that the nuts should not be loosened, but
just set the torque wrench to 70 Nm and tighten in the correct order. If you have a "real"
torque wrench, it will release at the set value. Nuts 3 and 5 are "outside" the valve cover.

On our engine, it is impossible to check nut 1 and 5 with a torque wrench without disassembling
additional parts. So I usually just take a regular 15 mm ring spanner and tighten "roughly" the same
amount as the other nuts. Nut 1 sits "under" the valve bridge and nut 5 sits with the leak oil pipe out of
the way of the large torque wrench. You might be able to bend the leaking oil pipe, but I dare not
do that. Leaking oil pipes are the "return" of excess diesel that is not injected into the engine.

Figure 6.8 Check and tighten the nuts 70 Nm in order. NOTE: to draw 1, the valve bridge must
actually be dismantled. To draw 5, the leak oil pipe that goes from the distributor must be
dismantled. Note that the cooling water connection is also dismantled from the exhaust manifold,
otherwise it is not possible to remove the valve cover on our engine.
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Figure 6.9 The torque wrench is now on nut 3, which is tightened to 70 Nm.

NOTE After the control draw, the valves must be adjusted. But first the engine must be
warmed up. Just make sure the valves are not completely wrong.

6.3 Valve adjustment

The valve clearance must be checked after every 50 operating hours. NOTE: before adjusting the valves,
the cylinder head bolts (head cap bolts) can be checked, see chapter 6.2. According to Volvo Penta, it is
very important that the valves are correctly adjusted, otherwise noise or, in the worst case, valve
failure can occur.

According to my father, who was production manager at the Garphytte mill in the 1970s, Volvo Penta's
engines have springs from Garphyttan. They will never break and they are very "shape stable". He thinks it
is excessive to adjust the valves after only 50 hours of operation.
Personally, I think that every time the valves have been adjusted, the engine runs better, i.e. the
color of the exhaust gases has improved.

- Warm up the engine as adjustment must always be done on a warm engine.

- Remove the valve cover. Use a 5 mm Allen key. To do this on our boat I recommend removing
the shelf first, also the cooling water line to the exhaust manifold is in the way and must
be unscrewed from the exhaust manifold first. Use a 10mm socket wrench, be careful not to drop
the screws behind the motor. Also take care of the gasket so it doesn't come off. Be careful not
to bend the metal on this wire as I believe it is very expensive to replace.
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- Turn the engine flywheel in the direction of rotation (clockwise) until the valves on the cylinder
seesaws. Then turn one more turn and adjust the valves.
- Insert a blade measurement according to picture 6.10, 6.11 and 6.12. The blade thickness measurement
must be 0.3 for inlet and 0.35 for outlet. The intake valve is closest to the flywheel and the
exhaust is closest to the exhaust manifold. When the valve clearance is correct, the blade
gauge should be able to slide in without any major resistance and only a slight friction should
be felt when the blade gauge is pulled back and forth.
- If the clearance needs to be adjusted, loosen the lock nut on the adjusting screw and then turn the
adjusting screw so that the correct clearance is obtained. Tighten the lock nut and check that
the play has not changed. It's a bit fiddly as the slightest movement of the screwdriver causes the
distance to change.
- Check the gasket on the valve cover, replace a damaged gasket. Reassemble everything.
Start the engine and listen for any abnormal noises.

Figure 6.10 Valve adjustment. I usually use a 13mm ring spanner as ½" which does what the
manual says won't fit,, screwdriver and blade gauge. In the picture it is the intake valve
that is adjusted to 0.3 mm, the blade gauge is in place.
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Figure 6.11

Picture 6.12, 13mm ring spanner and short screwdriver. According to the manual, you should use a ½" wrench,
but on our engine a 13 mm wrench fits better. An attentive reader pointed out to me that there is only a 0.3mm
difference between ½” and 13mm.

7. The exhaust system

The exhaust gases are water-cooled, i.e. all the water that the water pump sucks from the lake is pushed out
together with the exhaust gases. Water should splash out with the exhaust gases, this shows that the
cooling is working. By looking at the exhaust gases, you can easily check the condition of the engine, see
chapter 7.1.

The exhaust bend is slowly rusting from the inside. Check the underside so it doesn't look too rusty. A new bend
costs over SEK 3,000. There are cheaper "pirate parts" in stainless that are cheaper. Note that you may
think it is better with stainless exhaust bends. But if you install one like that, you run the risk of galvanic currents
that slowly destroy the cast iron in the cylinder head. I therefore recommend Volvo Penta's original exhaust bend.

The exhaust gases are led to the muffler and further via a gooseneck out of the boat. The task of the gooseneck
is to ensure that seawater does not penetrate the back way into the engine.

7.1 Exhaust fumes

You can determine the condition of the engine by looking at the exhaust gases. Warm up the engine, pull to full
speed quickly (gear in neutral) and return to idle. At the same time, look at the color of the exhaust gases.
There will be some black soot coming out on the water but that is normal.

• Thin white smoke that quickly dissipates = normal, everything is fine. • Thick
white smoke: Too hot, cooling water is heated up to steam. It can leak in
water in the cylinder due to a broken cylinder head gasket (head gasket). Stop immediately and act
as soon as possible. • Blue exhaust:
lubricating oil burned due to worn valve guides or piston rings. • Black smoke: Poor combustion of diesel.
The most common is that the valves are incorrectly set and need to be adjusted.
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7.2 Exhaust gas temperature sensor

It is important that cooling water is constantly mixed with the exhaust gases, otherwise the hose can be burnt and
there is a risk of fire. We have therefore fitted a temperature gauge which is attached to the outside of the exhaust
manifold and alarms if the temperature gets too high. A sensor for an oven thermometer is attached with galvanized
hose clamps (not stainless). The cable goes to a display where you can set an alarm signal to a value you decide
yourself. If it starts to get too hot, you get an alarm at an early stage.
, The temperature rarely goes above 40
degrees, so we have set the alarm limit at around 50 - 60 degrees.

8. Other engine controls

The motor has two wire controls. On our boat, these controls are in the aft stowage compartment, see picture 8.1.

The stop switch is pulled out to stop the engine. You simply stop the supply of diesel in the high-pressure pump.

The cold start control is pulled out for a cold engine to start more easily. It should be pushed in immediately after
starting when the engine is running smoothly. You can ignore this control and only use it if the engine bulls
and does not want to start. I've noticed that other MD5 owners apparently never use this slider. On our boat,
we almost never use the cold start. I don't really know what to do. As far as I understand, only the
amount of diesel changes, i.e. the same as giving more gas. I can't see that you change any time factor in the
high pressure pump.

Figure 8.1, shows cold start controls and stop

controls. Stop control furthest aft.

If the engine does not stop even though the stop switch is pulled out, you can use the decompression
handle on the valve cover ( see picture 1.1). If you have a leak at the feed pump, diesel can be added to
the engine oil, when it becomes "overfilled" the engine will run out of control by starting to suck engine
oil instead. it can be stopped by using the decompression glove. Alternatively, you can try to
block the air intake. But it is more difficult and dangerous as you have to reach
in next to the flywheel and risk getting your hair or clothes caught.
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9. Winter preservation
Winter preservation begins before the boat is lifted out of the lake. It's pretty easy and nothing to worry
about as long as you follow the steps below.

Oil and oil filter are changed in connection with take-up in the autumn. The advantage is that the engine
runs with fresh oil over the winter. Old oil can break down the engine.

A properly maintained and regularly checked cooling system minimizes the risk of overheating
damage. The biggest reason why the engine's cooling ducts rust is substandard preservation. When the
engine is empty of water and there is oxygen in the ducts, the breeding ground for rust attack is greatest.
It matters less if the engine is sea water cooled (fresh water cooled). To avoid frost blasts
and corrosion damage during the storage period, it is important that you preserve the cooling
system when the boat is occupied.
Preservation of the cooling system must be done on land, You can also do the preservation in the lake, but
the environmental aspect of pumping glycol into the lake is not good.

When picking up, you must make sure that you either have the tank completely full of diesel or it must
be completely empty. The reason for this is that in this way you reduce the risk of condensation and
thus water in the fuel, which leads to problems the following spring. Bacteria grow if there is water in the
fuel.

If you have a pre-filter (i.e. extra fuel filter) with a water separator between the engine and the tank, if
necessary water is drained before winter rest. If you have had problems with dirt in the fuel and
clogged filters during the season, this is a golden opportunity to thoroughly clean the fuel tank during
the winter.

9.1 Buy the following new parts

- Membrane for the vacuum valve, - Oil
filter and new engine oil Mineral oil SAE10W/30 CD - Filter for pre-
filter and fine filter, - Any new gasket
for the impeller housing

9.2 Warm up the engine, change engine oil and filter

See section 3.1

9.3 Empty the water separator (possibly change all fuel filters)

There are divided opinions as to whether the fuel filter should be changed at take-up or at launch.
A minimum is to empty the water separator in the fall.

Change the pre-filter (extra fuel filter) and empty the water separator. Clean the fuel strainer (on
the feed pump). Change the fine filter (fuel filter). Bleed to start the engine.

9.4 Filling the fuel tank full To

avoid condensation, the tank must be full during the winter. Also tape the tank ventilation so that moisture
cannot enter. If there is condensation, it collects at the bottom of the tank and bacteria starts to grow. The
alternative is to empty the tank completely and clean it during the winter.
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9.5 Take the boat ashore

Place the boat on land.

Open all penetrations are open (they can freeze to pieces the first night on land).
Pump out any hoses that may contain water.
Immediately when the boat is loaded, you have to open and close all the ball valves a few times so that all the
water disappears. A valve can freeze to pieces already on the first night with a little frost outside. Then leave the
valves in the half-open position.

Empty the fresh water tank by pumping and pumping, if necessary top up with a splash of alcohol so the pump
doesn't freeze and do one or two pumps to distribute the alcohol. Then the two seawater pumps must also be emptied
through repeated pumping.

Now the most urgent thing is fixed, the actual winter preservation can be done the next day or in a couple of days,
but don't wait too long, if it gets cold the engine can freeze.

9.6 Change the oil in the 110S gear

Drain the oil from the gear as soon as possible. If

water has entered, the drive may freeze.

Drain the oil by removing the plug at the bottom.

Remove the dipstick and the oil drains faster. Refit the
plug and tighten it "just right". Keep in mind that the
sprocket is made of aluminum so don't pull too hard
to break the threads.

Then put a small funnel in the oil dipstick hole.

Measure out exactly the right amount of oil Picture 9.1, changing the oil in the 110S gear
in an oil jug and fill slowly so that it does not
overflow. Fill just under 1.8 liters. DO
NOT OVERFILL
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9.7 Drain the cooling water and dismantle the thermostat

See chapter 5.2 how to dismantle the thermostat. Then put the "cap" back so that the engine
can be run with the glycol mixture. There is a drain screw on the engine body on the side under
the air filter, on our engine an 11 mm wrench is used, see picture 1.5 point 9. If no water comes
out try clearing the hole with a piece of wire or a nail. I had to pry for a long time the first time I
was going to drain the water before a black gush followed by water spurted out.

If you don't dismantle the thermostat, you have to run the engine really hot so that the thermostat
is open to be sure to get glycol into all the cooling channels. It is not something I
recommend as you are never really sure that you will get glycol water in. You can never be sure
that you really get glycol water in if you leave the thermostat on.
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9.8 Flush the cooling system with glycol

Use last autumn's glycol mixture or mix at least

2 liters of glycol with 2 liters of water (50%) in a
bucket. Disconnect the hose on the suction side of
the seawater pump and connect a longer hose that
reaches down to the bottom of the bucket.
Put a hose clamp so that it is tight so that the
pump is guaranteed to suck.

Check that nothing is destroyed at the

exhaust. You can collect the liquid in a bucket
and run several times. Figure 9.2, mix antifreeze liquid and run the
mixture through the engine

9.9 Impeller

See section 5.2 about the impeller.

Unscrew the cover to the seawater pump.

Remove the impeller and refit the cover. Drain
the water trap and exhaust line by starting the
engine and let it run for 5 -10 seconds.

Check that the impeller looks "healthy". It must be

changed every two years.

Figure 9.3, impeller replacement

NOTE see the section on impeller how to
remove it.

9.10 Mount the thermostat

See section 5.2 how to reassemble the thermostat. Can also be installed in the spring with the boat in the
water, but it is easier to do it when the boat is on land.

9.11 Clean the vacuum valve

See section 5.3 about the vacuum valve.

9.12 Other controls

Check the charge in the batteries. Fully charged batteries can be left over the winter.
Otherwise, they must be taken home and charged. Cold batteries have lower self-discharge. Place the
batteries in a cool area at home.
Spray electrical connections with anti-corrosion oil.
Check all rubber parts.
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9.13 Disassemble the folding propeller

Older model of iron. Newer model of bronze (until 2004).

From the year 2005 there is a similar model that has
Loosen the locking screws (a) for the blade sacrificial anodes on the propeller hub.
suspension pins, knock out the pins (b) and remove
the blades. Remove the cotter pin (c), loosen the First unscrew the safety screws (1) with an Allen
propeller shaft nut (d) and pull off the propeller key. Then push out the pins (2) for the
hub (e). Also remove the lens cutter (f). Apply propeller blades. Then remove the propeller blades
propeller grease to the shaft after cleaning. Protect (3). Then the locking (5) must be bent back
the shoulder during the winter with, for example, so that the bolt (4) can be loosened. Then the large
a plastic bag. special nut (6) must be loosened. Now
the propeller hub can be detached. NOTE
Take home and service the propeller. If you have the The locking (4) must be replaced every four years
older one made of iron, damage must be painted according to VP.
with epoxy paint so it is ready in good time before
launching. Also take the lens cutter home so it doesn't get lost
during winter storage.

Apply propeller grease to the shaft after

cleaning. Protect the shoulder during the winter
with, for example, a plastic bag.

Picture 9.4, older model of VP

folding iron propeller.

Picture 9.5, newer VP bronze folding propellers

(sold until 2004).
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Picture 9.6, latest VP folding bronze propellers that were introduced around 2004/2005. New is
that anodes are on the hub..
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9.14 Winter setup

Cover stand and tarpaulin Put on

cover stand and suitable tarpaulin. Make sure nothing rubs against the boat's surfaces.
The tarpaulin must not be tied to the cover stand, but must be attached to "hanging"
water cans and to the cradle. Make sure that air can circulate, i.e. open in the fore and aft.

Ventilation
There are two ways. Alternatively, you seal to 100% and put a dehumidifier in the boat, or you
ventilate. I think it is easier to ventilate as it is very difficult to make the boat airtight.

Disassemble the log and leave the hole open (for air circulation).
Leave the top engine cover open (for air circulation).
Make sure that air enters the upper edge around the locked ruff flap.
Make sure there is plenty of air in the stern and bow under the tarpaulin

Miscellaneous

Make sure that all textiles (pads), books and papers have been taken home.
Check that everything is done before winter.
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Launching

10.1 Before launching

Check the oil level in the engine and S-gear before launching. Open the tap
for the water intake on the S drive (if it was closed in the fall).
If you didn't change your fuel filter last fall, do it now!
If the thermostat has been picked out, it must be mounted now!

If the impeller was removed, make sure it is in place before starting the engine in the lake.
It is possible to run the engine carefully without an impeller, but it is perhaps a matter of a maximum of
60 seconds. Hot exhaust gases can destroy the exhaust pipe and silencer.

Check the sacrificial anode (zinc ring or magnesium for fresh water) on the S-drive, line guard and propeller.
There must be at least 50% of the sacrificial anode left.

Mount the propeller on a well-cleaned and greased shaft.

If you have the older VP iron folding propeller, a new locking pin (c) must always be fitted.

The bronze folding propeller must be mounted with a torque wrench, see figure 9.5. Tighten special nut (6) with
70 Nm. I have seen several suggestions on how to do it, but one thing is for sure, you cannot tighten the bolt (6)
with a propeller blade mounted as shown. Instead, you have to insert a propeller blade into the hub without the
bolt (2) and hold it against the hull with a piece of wood.
Place the locking catch (5) NOTE must be replaced every four years. Tighten the locking bolt (4) with 20 Nm. Then
put in the propeller blades. Note that the small derailment on the shaft (2) should be where the locking bolts (1)
are inserted. Tighten with 20 Nm. The locking bolts must be thoroughly lubricated. Finally, apply
plenty of propeller grease to the blades' teeth.

Usual spring armoring of the boat.

The boat is now ready for launching. NOTE Start attempts must only be made when the boat is in the lake.

10.2 When the boat is in the water

Warm-up for about 20 minutes, in the meantime check the hoses and connections so that no leaks have occurred.
If water is leaking from the thermostat housing, you may need to shake the connections a bit, or
alternatively buy new rubber gaskets. Check the function of the control by switching back and forth a few
times. Stop the engine and check the oil level in the engine and drive.

If you didn't change the oil last fall, it must be done now! NOTE It is best to change the oil in the fall.
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11. Service after 50 hours of operation - or at least once per season

Change engine oil (filter after 100 hours)

Check valve clearance
Check tightening of cylinder head nuts (cylinder head nuts) (after 100 hours)
Fuel filter replacement and filter cleaning (after 100 hours)
Then you also have to change the oil in the gear after 200 hours, but to do this the boat has to be
out of the water. So it is something you do once a season in connection with the
winter recording.
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Service parts

Here are the most important parts for the MD5 that you should have with you in the boat to cope with a
simpler downtime.

- Fan belt: o
*
1350mm 9.5mm, only applies to NF 351 with rebuilt generator. (Is on
Meconomen and Biltema) o
Standard VP article number 966698,
Costs SEK 141 (2006) at Erlandsson's bridge

- Thermostat seawater cooling: o VP

article number 875.783, 3 rubber sealing rings may also be needed
for pipes VP article number 829714-5,
At VP, the thermostat with gasket costs just over SEK 500, which makes it one of
the world's most expensive thermostats available for purchase.
o Thermostat with gasket from Orbitrade, item 15783
Costs SEK 306 at Carfix Västerås (2005)

- Impeller, same impeller as MD5A/B/C, MD6B, MD7A/B, MD11, 2001, 2002

and in 2003:
o VP article number 3586496 including gasket for the lid
Costs SEK 199 (2007) at Hjertmans (SEK 191 in 2006)
Costs SEK 191 (2006) at Erlandsson's bridge and
JP impellers, JP no: 09-808B
Costs SEK 165 (2006) at SeaSea
- Oil filter: o
Volvo Penta article number 834337, also used for Volvo Penta engines 1 – 3 cylinder
diesel engines except MD20x0 and D1. MD1A/B,
Costs SEK 123 (2007) at Hjertmans (SEK 117 in 2006)
costs SEK 116 (2006) at Erlandssons brygga o Fram
PH2874 for Renault R4 (950cc), R4GLT, R5L and R6 (850cc)
Costs SEK 106 (2006) at SeaSea
Costs about SEK 100 (2005) at Carfix in Västerås
o Mann, filter W 77, UPC/EAN Code 4011558700102, Bypass valve opening
pressure 0.7 bar, with anti-drainback valve
o Biltema's filter article 50-659 for Renault R4, R5TS/TL/GTL (1977-1984),
R15TS, R16TS/TX, R17TL,
costs 49:90 at Biltema (Spring 2006)

- Pre-filter type CAV

o Volvo Penta article number 358178-7 costs
67:- (2007) at Hjertmans (64:- 2006) costs 66:- (2006)
at Erlandsson bridge
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- Fuel filter (insert filter) for MD5A/B also for MD1B, MD2B, MD3B, MD17C
o Volvo Penta article number 876554
Costs SEK 132 (2007) at Hjertmans (SEK 127 in 2006)
Costs SEK 127 (2006) at Erlandsson's bridge
o MANN Filter P715, UPC/EAN Code 4011558550608 (NOTE gasket included
not)
Costs SEK 124 (2005) at Carfix in Västerås and
beyond C11859PL
Costs SEK 115 (2006) at SeaSea

- Engine oil, 4 liters of engine oil, mineral oil SAE 10W/30 CD Mineral oil (not synthetic).
Buy, for example, Biltema's cheapest Mineral oil in 4 liter cans.

These parts must always be with the boat. The boat somehow senses that everything is included and
then of course nothing happens. Try to pick something out and it's bound to go wrong.

For more information, see the chapter on spare parts, which contains information on which spare parts are
available for purchase.
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13. Dimensions and tables

Figure 13.1, dimensions MD5A and MD5B with 110S

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Figure 13.2, Dimensions MD5C with 120S

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Figure 13.3, MD5A and MD5B, the graphs show fuel consumption, torque and power.
NOTE The diagrams are based on the engine operating at full throttle at all revs and are
obtained if you run the engine in a brake bench. A marine engine can never work this way so
this type of table is rather pointless. The engine must, with the right propeller, be able to reach
its maximum speed of 2500 revolutions. But it should normally be run at 70-80% of the maximum
rpm, i.e. 1750-2000 rpm.
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14. Technical Data MD5, applies to all models

Generally
Engine designation with S drive MD5A/110S, MD5B/110S, MD5C/120S
Engine designation with reverse stroke MD5A, MD5B, MD5C 4-
Working stroke diesel with direct injection 1 5.5 kW, 7.5
Cylinders
Propeller shaft power at 2500 r/m hp (MD5A, MD5C) 7.0 kW, 9.5 hp
Propeller shaft power at 3000 r/m (MD5C) 2500 r/m, 41.7 r/s
Max operating speed ( MD5A, MD5B) 3000 r/m, 50 r/s (MD5C) 84
mm 80 mm 0.443 dm3 20 – 22
Cylinder diameter kp/cm2
Stroke length (starting
Stroke volume engine speed)
Compression pressure (equivalent to 19.6 – 21.6 bar) approx. 700
r/m, approx. 12 r/s
Idle revolutions
Direction of rotation viewed from flywheel Clockwise
Engine tilt while running
Backward 15 degrees
max. To the sides max 20 degrees
Engine weight with recoil 111 kg (MD5A, MD5B) 116
kg (MD5C) 128 kg
Engine weight with 110S (MD5A, MD5B) 119 kg (MD5C)
Engine weight with 120S

Propeller 14*8 bronze folding 6.7 kg (weighed)

Weight of lubricating oil (2.2 + 1.8 liters) and diesel in filters and pumps approx. 4.5 kg
Total weight engine, S-drive, propeller, oils estimated approx. 139 kg (MD5A, MD5B)
Total weight engine, S-drive, propeller, oils estimated approx. 130 kg (MD5C)

Valves
Valve clearance hot engine
inlet (closest to flywheel) outlet 0.3mm
(closest to exhaust manifold) 0.35mm

Backlash
Type designation MSB
Gear forward and reverse 1.91:1

S-Drive
Sailboat drive, type 110S (MD5A, MD5B) 1.66:1
Exchange or 2.15:1
Serial numbers (PZ) from 1116831 have 2.15:1
Our boat has the older type with 1.66:1

Sailboat drive, type 120S (MD5C)

Exchange 2.20:1
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Lubrication system
Engine
Oil amount in engine 2.0 l without oil filter, 2.1 l with oil filter
Oil quality Diesel Lubricating Oil Service CD
Viscosity SAE 10W/30
Oil pressure, warm engine, idle at full 1.5 – 2.5 kp/cm2 4.0
revs – 5.0 kp/cm2

Backlash
Type designation MSB (MD5A, MD5B)
Transmission "forward" and "reverse" 1.91:1
Oil quality same as engine 0.55 l
Oil amount (MD5A manual) 0.6 l (MD5B manual)

Type designation MS2 (MD5C)

110S Drive (MD5A, MD5B)

Oil quality same as engine 1.8 l
Oil quantity
In the instruction manual for the MD5B it says 2.3 liters which is incorrect

120S Drive (MD5C)

Oil quality same as engine?
Oil amount

Cooling system
Thermostat, starts to open at is 60 degrees +-2 degrees
fully open at 90 degrees (MD5A instruction book) 75
degrees (MD5B, MD5C instruction book)
Note that a different thermostat is used for closed fresh water cooling.
The inside diameter of the radiator hoses 16 mm

Fuel system
Injection pump, make Feed Bosch
pressure 0.75 kp/cm2
Injector, holder make Opening Bosch
pressure Pre- 180 kp/cm2
injection angle, crankshaft degrees b.f. 24 – 27 degrees
Fuel quality "Autodiesel" Cetane number minimum 45

Electrical system
Battery voltage 12 V
Alternating current generator original Marchal 35A (420 W) MD5A, MD5B)
Marchal 50A (MD5C)
Alternating current generator in NF 351 Valeo 70A
Starter motor 0.8 KW (1.1 hp)
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Tightening torque
Cylinder head nuts 7.0 kpm, 70 Nm
Connecting rod bolts 7.0 kpm, 70 Nm
Crankshaft frame bearing 7.0 kpm, 70 Nm
Flywheel nut 50.0 kpm, 500 Nm
Injector nuts 0.8 kpm, 8 Nm

Threads donor
Oil pressure sensor 1/8” NPTF
Water temperature sensor M18 * 1.5 mm
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and engine refurbishment

Service parts that must be included in the boat see chapter 12.

Sooner or later there comes a point when you have to decide whether to refurbish your old MD5A or replace it. MD5
has one important advantage – it is small. Both length and height of the engine are difficult to match with a new engine.
The MD5 is single-cylinder and thus "short".
On our boat, it is difficult to fit a longer engine, so there are good reasons to take care of your old engine.

An alternative could be to buy a refurbished MD5 as it fits right away and you don't have to change anything else.
You can then keep the old one as travel parts stock for the future. A used MD5 costs from the free picking job up
to around SEK 20,000 for a tested engine with 110S/120S drive and warranties. The advantage of buying an
identical engine is that you don't have to rebuild anything.

15.1 Volvo Penta spare parts

Every year, Volvo Penta publishes a catalog called "Spare parts & Accessories". I have compiled the MD5 parts that
are included

Alternator belt
MD5A/B/C Art no 966698 SEK 142 (2006)
MD5C from engine no. 30017 Item No. 976492 SEK 249 (2006)

Sacrificial anode rate

110S drive Zinc Item No. 875812 SEK 244 (2006)
110S drive Magnesium (for fresh water) Item No. 876603 SEK 405 (2006)

Cleaning kit
Contains cylinder head gasket and other gaskets needed when lifting the cylinder head (cylinder head).

MD5A/B/C Item No. 876341 SEK 716 (2006)

Additional rate
Contains sump gaskets and engine seals
Used if the engine is to be completely renovated
MD5A/B Art no 876381 SEK 1,206 (2006)
MD5C Art no 876382 SEK 978 (2006)

Piston ring kit

MD5A Art no 875566 SEK 750 (2006)
Exhaust bend
MD5A ? ?

Gasket for exhaust manifold

MD5A Species no ?

MD5C Item No. 831960

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*
Temperature sensor, thread M18 1.5
MD5A/B/C, MD6B, MD7A and
the following engines with fresh water cooling: MD2B, MD3B, MD11 C/D, MD17C/D, SEK 482 (2006)
Item No. 833927

Oil pressure sensor, thread 1/8” NPTF

MD5A/B, AQ110, AQ 120, MD2, MD2B, MD3B, MD6A/B
Item No. 807078 SEK 142 (2006)

Drain tap 1/8” for MD5A/

B, MD1, MD2, MD3B, MD6A
Item No. 807036 SEK 93 (2006)

Rubber seal for S-Drev

110S Item No. 872026 SEK 2,454 (2006)
Costs SEK 2,382 at Erlandsson's bridge (2006)

Cover plate against hull

110S, 120S Art no 854932 SEK 560 (2006)

Cylinder head, cylinder head

Consists of cylinder head, intake and exhaust valve, valve springs, washer and lock, as per
VP catalog is also needed for tube 838366
MD5A/B/C Art no. 3803085 SEK 7,447 (2006) cost SEK 6,881 in the catalog
in 2004

Injector
MD5A/B/C Art no 3803230 SEK 1,564 (2006)

Starter motor
MD5A/B/C Art no 3803077 SEK 6,912 (2006)
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For the handy, there are some spare parts and kits to buy (all prices from 2005). Drevia in Lysekil (www.drevia.se)
sells a renovation kit consisting of cleaning kit (gaskets for the upper part of the engine), additional kit
(gaskets for the lower part), crank bearing, cylinder liner, piston, piston bolt, piston rings, o-ring kit for about SEK
6,500 .
Frame bearing set (without thrust bearing) SEK 4,100.
A new complete ball-bearing seawater pump SEK 2,900.
New starter motor SEK 6,710 (exchange, old in return).
You can also buy a replacement cylinder head with intake and exhaust valves, valve springs, washer and lock for SEK
7,230.

Feed pump is available to buy as a complete spare part, see picture 15.1. It is the same pump as for MD1B/2B/3B/5/6/7.
The same feed pump also fits MD2001/2002/2003/2003T early models up to and including engine number 2300046825.

Feed pump 833.323, Gasket approx. SEK 1,600,

connection (4 needed) 957.178: O-ring against engine approx. SEK 5/

block 942.353 Diaphragm kit with strainer each approx.

834.255 SEK 15 approx. SEK 1,100

Figure 15.1, Feed pump 833.323

It appears that Volvo Penta (2007) has discontinued the feed pump. Drevia has a replacement pump that costs
less than SEK 1,000.

Exhaust elbow
It is cheaper to buy a stainless exhaust elbow from Swenautic Tedo AB in Frölunda than to buy cast iron Volvo
Pentas. Cast iron rusts and if it "breaks" you can actually sink the whole boat. NOTE Stainless causes galvanic
corrosion so the cylinder head can rust. I therefore recommend the old type of cast iron for MD5.
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Troubleshooting

16.1 If the engine stops or does not start

First check that the stop wire is pushed back so that it is not stuck. Another very easy thing to check is that
the decompression valve on the valve cover is closed.

If the engine stalls or does not start, there is usually a problem with the fuel system.
Check if there is fuel left in the tank, if not top up.

You may need to bleed the fuel system. Bleeding means removing the air in the engine's fuel system. Air
bubbles stop the fuel supply in a diesel engine. It's not hard to do but can be a bit messy. If it doesn't help
and no fuel comes out, it's stopped. It could be debris from the tank clogging the filters. Some tanks
have a small strainer at the bottom that sits next to the suction tube. By blowing air backwards through the
entire fuel line, you can remove the debris (temporarily) from the strainer.

If you notice that filters are very dirty with debris, it may be time to clean the diesel tank. If the hose that
goes from the tank and the fuel hoses at the engine are old, replace these as well.

The fine filter (the older model with an insert) has a gasket between the metal bowl and the top that almost
always gets tangled.

For more information see chapter 2 and especially chapter 2.5 on ventilation.
If the engine starter does not move, there is a problem with the electrical current in some way.
First check that the motor's main switch is switched on. Also check all cables to make sure there is a good
connection everywhere. See chapter 4 and especially 4.1.

16.2 The motor panel alarms

If it starts to howl and a warning light comes on on the engine panel, you need to be quick. Look which
lamp is on.

OIL = red light, oil pressure error, stop the engine immediately, see chapter 3.3

TEMP = red light, temperature too high, take a quick look at the exhaust, is there water coming out? If yes,
it's probably just the thermostat, if no, it's a blockage in the cooling water.
Could be the impeller, could be a blockage at the water intake, could be a leak in the cooling system, could be
a rusted thermostat cover or blocked cooling ducts. See chapter 5. If you have fresh water cooling,
there may be rust flakes in the extra water filter that you should have, or the heat exchanger is clogged and
needs cleaning.

AMP = yellow light, no charging from the generator. You can run the engine, there is nothing to
break, but realize that no new charge is added to the batteries.
See chapter 4.