Vishal Patel

Excessive fuel consumption

CAUSES REMEDIES
Excessive fuel pump pressure or
1 Reduce pressure; repair pump.
pump leakage.

2 Choke partly closed after warm-up. Open; repair automatic choke.

3 Clogged air filter. Replace or clean the filter element.

Adjust the caburettor float level as
4 High carburetor float level.
prescribed.
5 Dirty or stuck float needle valve. Clean or free the float needle valve.
6 Worn carburettor jet. Replace carburettor jet.
7 Idle too rich or too fast. Adjust as prescribed.
8 Carburettor leaks. Replace gaskets and tighten screws.

9 Stuck accelerator pump check valve. Free valve.

10 Short-run operation. Drive longer distance.

 Engine overheating
CAUSES REMEDIES
1. Incorrect ignition timing. Adjust as prescribed.
2. Loose or broken fan belt. Tighten or replace.
3. Defective thermostat. Replace.
4. Clogged water jackets. Clean water jackets.
5. Defective radiator hose. Replace.
6. Defective water pump. Repair or replace.
Add adequate amount of
7. Insufficient engine oil.
engine oil as prescribed
8. Incorrect valve timing. Adjust as prescribed.
 Engine’s one cylinder missing
CAUSES REMEDIES
1. Defective spark plug. Replace.

2. Defective distributor lead

Replace.
or cap.

3. Valve stuck open. Free valve; service valve guide.

4. Defective piston or rings. Replace.

5. Defective head gasket. Replace.

 Engine cranks normally but does
not starting
CAUSES REMEDIES
Try sparking test; checking timing, ignition
1. Defective ignition system.
system.
Prime engine; check accelerator-pump
2. Defective fuel system. discharge, fuel pump, fuel line, choke,
carburator
3. Air leaks in intake manifold or Tighten mounting; replace gaskets as
carburator needed.
Check compression or leakage, valve
4. Defective engine.
action timing
5. Ignition coil or resistor burned
Replace.
out.
6. Clogged fuel filter. Clean or replace.
 Engine is loosing power
CAUSES REMEDIES
Check carburetor, choke, filter,
1. Defective fuel system.
air cleaner and fuel pump
2. Throttle valve not opening fully. Adjust linkage.
3. Excessive carbon in engine. Service engine.
Check with compression,
4. Defective valve action.
leakage, vacuum.
5. Wrong or bad fuel. Use correct octane fuel.
6. Heavy oil. Use correct oil.
Check timing, distributor,
7. Defective ignition.
wiring, condenser, coil and plug
 Noisy engine
CAUSES REMEDIES
1. Worn or broken piston rings. Replace.

2. Loosely mounted accessories;

alternator, horn, oil pan, front, bumper, water Tighten mounting.
pump, etc

3. Worn main bearing and thrust bearing Replace.

4. Loose piston pin. Tighten.

5. Worn connecting rod bearing. Replace.

6. Worn crankpin. Replace.

 Piston “SLAP”
CAUSES REMEDIES

1. Worn pistons. Replace.

Replace connecting
2. Misaligned connecting rods.
rod.
3. Collapsed piston skirts. Replace.

4. Lack of engine oil. Add oil.

 Valve and Tappet Noise
CAUSE REMEDIES
1. Weak or broken valve springs Replace

2. Worn lifter faces. Replace

3. Lifters loose in block. Tighten.

4. Rough cams. Replace

5. Excessive tappet clearance. Adjust the clearance as prescribed.

6. Defective hydraulic valve lifter. Repair or replace.

7. Excessive wear of one or more cams of
camshaft. Replace.

8. Excessive push rod-to-guide clearance Adjust the clearance as prescribed

9. Excessive valve steam-to-guide bore
clearance Adjust the clearance as prescribed
 Engine vibration
CAUSES
• Defective ignition.
• Defective carburetor.
• Crankshaft out of balance.
• Clutch out of balance.
• Connecting rods and pistons of unequal weight.
• Mal-adjusted valves.
• Misaligned engine-transmission-propeller shaft.
• Too stiff engine supports.
 Engine backfires
CAUSES • Ignition timing off.
• Spark plug of wrong heat range.
• Excessive rich or lean mixture
• Overheating of engine
• Carbon in engine
• Cracked distributor cap
• Valves hot or sticking
 Causes Black Smoke
CAUSES • Choke in operation
• Spark plugs not functioning satisfactorily.
• Clogged air filter
• Punctured or incorrectly set carburettor float
• Worn out or wrong size jets
• Needle valve stuck open.
• Ignition system erratic
• Incorrect ignition timing.
• Worn out, stuck or broken piston rings
 Causes of Blue Smoke
CAUSES
• Excessive petrol mixture ratio.

• Excessive oil in clutch chamber.

• Crank case oil seals worn out or damaged.

• Worn out, stuck or broken piston rings.

• Worn out cylinder bore.

 Engine Tune Up
 To Restore the Engine Performance after
certain usage.

 Engine Repowering
 Minor Tune Up

1 • Visual Inspection

2 • Mechanical Service

3 • Instrument Test
 •Visual Inspection
Condition Checking of
Engine Mountings & other attachments

Check Wiring, Hose pipes, Belts,

Carburetor linkages

Check coolant, oil, fuel, Exhaust leakage,

etc
 •Mechanical Service
Tighten the Bolts with Torque Wrench
(if necessory)

Check Wiring, Hose pipes, Belts, Carburetor linkages

Check coolant, oil, fuel, Exhaust leakage, etc

Condition Checking of
Engine Mountings & other attachments
 •Instruments Tests
Engine Timing, Timing Advance,
Mechanism, Engine Idle setting check

Cylinder Balance check

Exhaust Gas Analysis

Compression Test, F.I. Pump Setting

 Major Tune Up
1 Observe the Engine Running by sound

2 Observe the Engine performance by Exhaust gas analyzer.

3 Remove Spark Plug, Injector and open the Throttle valve

4 Check the compression test

5 Replace spark plug if needed

6 Check battery level & other electricals.

7 Inspect the starting system

8 Inspect the Drive belt. Replace if needed

9 Check Distributor, Rotor, cap , contact point gap, breaker cam

 Major Tune Up
10 Set the ignition timing

11 Inspect fuel pump, filter and fuel line. Change oil + filter

12 Air Cleaner Cleaning

13 Inspect the cables.

14 Inspect the cooling system. Replace the component if needed

15 Tighten the bolts of Engine with appropriate torque.

16 Set engine rpm.

17 Check Exhaust gas before and after tune up

 Major Overhaul Minor Overhaul

Generally after Generally after

1
80,000 – 1,00,000 Km 30,000 – 40,000 Km
Oil change + Oil chamber
2 Only oil change
service

3 Engine head is opened not opened

4 Piston rings changed not changed

5 Drive belt changed Not changed

Battery top
6 Battery replaced
up/charging
 Major Overhaul Minor Overhaul

7 Compression test done Not done

8 Reboring done sometimes Not needed

Sometimes Piston + Liner

9 Not done
Replacement needed

10 Reverse flush the radiator Not don

11
Change hose pipe & Fan Change only if
belt needed
 Excessive clearance
between
Piston and Cylinder
1 Compression leak ( Power Loss)

2 Blowby gas

3 Oil consumption more

4
Exhaust gas leak in crank case (oil
deterioration)
5 Piston slap
 Low (Less) clearance
between
Piston and Cylinder
1 Scratches on Piston & Cylinder

2 Chances of Piston seizure

3 Friction loss increase

4 More wear on Piston & Cylinder

The End