3116 Marine Engine 4KG00001-UP(SEBP1874 - 26) - Documentation Page 1 of 4

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Product: MARINE ENGINE

Troubleshooting
3114, 3116 and 3126 Engines
Media Number -SENR6502-06 Publication Date -01/07/2010 Date Updated -28/07/2010

i01156782

Low Power
SMCS - 1000-035; 1250-035

Probable Causes
• Excessive load

• Poor fuel quality

• Plugged fuel filter or plugged air filter

• Excessive engine oil

• High fuel temperature

• Air inlet leak after the turbocharger

• Exhaust leak before the turbocharger

• Air inlet restriction or exhaust restriction

• High air inlet temperature

• Fuel ratio control setting

• Binding in the fuel injection control linkage

• Damage to the valve train or damage to the unit injectors

• Improper fuel injection timing

• Incorrect valve adjustment

• Incorrect fuel setting

• Faulty turbocharger

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• Low fuel pressure

• Air in fuel

• Faulty unit injector

• Low cylinder compression

Recommended Repairs
Excessive Load

Ensure that the engine is not operating under an excessive load. Excessive load can be caused by
any of the following conditions:

• High altitude operation

• Low tire pressure

• Parasitic loads

Poor Fuel Quality

Ensure that the vent for the fuel tank is not plugged. Ensure that there is good, clean fuel in the
tank. When possible, interview the operator in order to determine if fuel quality is in question.
Refer to Troubleshooting, "Fuel Quality".

Plugged Fuel Filter or Plugged Air Filter

Inspect the air filter. Replace the air filter, if necessary. Check the water separator (if equipped). If
the fuel filter has not been replaced recently, replace the fuel filter.

Excessive Engine Oil

Check the engine oil level. If the engine oil level is high, drain the oil. Refill the system to the
correct level. Determine the source of the extra oil. If the oil is diluted with fuel, locate the fuel
leak and repair the fuel leak. Refer to Troubleshooting, "Fuel In Engine Oil".

High Fuel Temperature

Verify that the temperature of the fuel in the fuel tank is less than 78 °C (172°F). A low fuel level
in the fuel tank can cause high fuel temperature. Check for proper operation of the fuel heater, if
equipped.

Air Inlet Leak After the Turbocharger

Check for loose connections between the turbocharger and the inlet manifold. A small air leak can
cause problems when the engine is operating under full load. Check the aftercooler for visible
signs of leaking. A soap solution can be used to detect leaks. Allow the engine to cool before the
soap solution is used.

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Exhaust Leak Before the Turbocharger

Exhaust leaks between the exhaust manifold and the turbocharger can reduce boost pressure.
Check for exhaust leaks at the exhaust manifold. Also check for exhaust leaks at the mounting
flange for the turbocharger.

Air Inlet Restriction or Exhaust Restriction

Measure the air inlet restriction and measure the exhaust system restriction. Refer to Systems
Operation, Testing And Adjusting. Measure the air inlet restriction at the inlet of the turbocharger.
The maximum inlet restriction is 6.2 kPa (25 inches of H2O). Measure the exhaust restriction after
the turbocharger. The maximum exhaust restriction is 10 kPa (40 inches of H2O). Refer to
Technical Marketing Information (TMI) for additional data.

High Air Inlet Temperature

Check for proper operation of the air inlet heater (if equipped). Measure the inlet air temperature.
Compare the inlet air temperature to the specification for the inlet air temperature that is listed in
the TMI. If the inlet air temperature is high, check the aftercooler for restrictions and also check
the aftercooler for proper operation.

Fuel Ratio Control Setting

To avoid personal injury, always wear eye and face protection when
using pressurized air.

Stop the engine. Remove the control line that connects the FRC to the inlet manifold. Apply 140
kPa (20 psi) to 200 kPa (29 psi) air pressure to the FRC. Listen for air leakage in the governor. If
leaking air is detected, replace the FRC. Check the setting for the FRC. Refer to Service Manual,
SENR6454, "3114, 3116 & 3126 Engine Governors".

Binding in the Fuel Injection Control Linkage

If the fuel injection control linkage is binding, refer to Troubleshooting, "Fuel Injection Control
Linkage".

Damage to the Valve Train or Damage to the Unit Injectors

Remove the valve cover. Inspect the following items for damage:

• Unit injectors

• Push rods

• Rocker arms

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Refer to Troubleshooting, "Unit Injector".

Improper Fuel Injection Timing

Check the fuel injection timing. Refer to Systems Operation, Testing And Adjusting, "Fuel
Timing".

Incorrect Valve Adjustment

Check the valve adjustment. Refer to Systems Operation, Testing And Adjusting, "Valve Lash".

Incorrect Fuel Setting

Check the fuel setting. Refer to Systems Operation, Testing And Adjusting, "Fuel Setting".

Faulty Turbocharger

Inspect the turbocharger compressor wheel. If excessive deposits are found on the compressor
wheel or the compressor wheel is damaged, determine the cause. If the cause is not found, the
problem will reoccur. Rotate the compressor wheel in order to check for dragging or binding.
Check for excessive play in bearings.

Low Fuel Pressure

Check the fuel pressure. Refer to Systems Operation, Testing And Adjusting. Minimum fuel
pressure with clean fuel filters is 50 kPa (7.3 psi) at low idle or 200 kPa (29 psi) at high idle. If the
fuel pressure is low, make sure that the fuel filters are not plugged. Premature plugging of the fuel
filter indicates excessive fuel system contamination. Ensure that the fuel system is clean. Refer to
Troubleshooting, "Fuel Transfer Pump".

Air in the Fuel

Refer to Troubleshooting, "Air In Fuel".

Faulty Unit Injector

Use the 1U-6661 Pop Tester Group to check the unit injectors for proper operation. Refer to
Special Instruction, SEHS9787. Use the go/no-go gauge to check the unit injector height. Check
the injectors for external leakage.

Low Cylinder Compression

Check for signs of broken piston rings, faulty cylinder head gasket, and worn cylinders or valves.
If the engine runs properly and there is not excessive blowby or excessive oil consumption, the
cylinder compression is probably acceptable.

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