Engine Performance Troubleshooting Tree for QSB5.9 Marine Engines with CM850 Electronic Control System
Symptoms
- Engine Acceleration or Response Poor
- Cranking Fuel Pressure is Low
- Engine Operating Fuel Pressure is Low
- Engine Decelerates Slowly
- Engine Difficult to Start or Will Not Start (Exhaust Smoke)
- Engine Difficult to Start or Will Not Start (No Exhaust Smoke)
- Engine Power Output Low
- Engine Runs Rough at Idle
- Engine Runs Rough or Misfires
- Engine Speed Surges at Low or High Idle
- Engine Speed Surges Under Load or in Operating Range
- Smoke, Black – Excessive
- Smoke, White – Excessive
- Engine Shuts Off or Dies Unexpectedly or Dies During Deceleration
- Engine Starts But Will Not Keep Running
- Engine Will Not Reach Rated Speed (rpm)
- Intake Manifold Pressure (Boost) is Below Normal
- Excessive Vibration in Marine Applications
How To Use This Tree
This symptom tree can be used to troubleshoot all performance based symptoms listed above. Start by performing Step 1 troubleshooting. Step 2 will ask a series of questions and will provide a list of troubleshooting steps to perform, depending on the symptom. Perform the list of troubleshooting in the sequence shown in the Specifications/Repair section of the tree.
Shop Talk
Operational is a term that in general describes vessel performance on the water. Operational problems for an engine can be caused by several different factors. Some of the factors are engine-related and some are
not. Before troubleshooting, it is important to determine the exact complaint and whether the engine has a real operational problem or if it simply does
not meet owner expectations.
Low power is a term that is used in the field to describe many different performance problems. Low power is defined as the inability of the engine to produce the power necessary to move the vessel at a speed that can be reasonably expected under the given environment.
Poor acceleration or response is described as the inability of the vessel to accelerate satisfactorily from a stop. It can also be the lag in acceleration at conditions less than rated speed and load. Poor acceleration or response is difficult to troubleshoot, since it can be caused by several factors.
Troubleshooting Steps
STEPS | SPECIFICATIONS | |
---|---|---|
STEP 1. | Perform basic troubleshooting procedures. | |
STEP 1A. Check for active fault codes or high counts of inactive fault codes. | Active fault codes or high counts of inactive fault codes? | |
STEP 1B. Perform basic troubleshooting checks. | Can the problem be verified? | |
STEP 1C. Perform basic troubleshooting checks. | All steps have been verified to be correct? | |
STEP 2. | Determination of engine symptom. | |
STEP 2A. Low power, poor acceleration, or poor response. | Is the engine symptom low power, poor acceleration, or poor response? | |
STEP 2B. Engine misfire, engine speed surge, or engine speed unstable. | Is the engine symptom engine misfire, engine speed surge, or engine speed unstable? | |
STEP 2C. Excessive white or black smoke. | Is the engine symptom excessive white or black smoke? | |
STEP 2D. Low intake manifold pressure. | Is the engine symptom low boost pressure? | |
STEP 2E. Engine will not start or difficult to start, engine shuts off unexpectedly. | Is the engine symptom engine will not start or difficult to start, engine shuts off unexpectedly? | |
STEP 2F. Engine vibration excessive. | Is the symptom engine vibration is excessive occurring when the engine is in or out of gear? | |
STEP 3. | Engine starting and running troubleshooting procedures. | |
STEP 3A. Verify the fuel supply and return valves are open. | Are the fuel supply and return valves in the open position? | |
STEP 3A-1. Check the fuel cooler for damage due to high fuel return back pressure. | ||
STEP 3B. Verify the low pressure fuel lines are routed correctly. | Are the low pressure fuel lines connected properly to the ECM cooling plate? | |
STEP 3C. Check the engine speed during cranking. | Is the engine cranking speed greater than 150 rpm? | |
STEP 3D. Check the ECM keyswitch voltage. | Is the keyswitch voltage equal to the battery voltage? | |
STEP 3E. Check the ECM battery supply voltage. | Is the ECM battery supply voltage equal to the battery voltage? | |
STEP 3F. Verify the rail fuel pressure sensor accuracy. | Is the rail fuel pressure sensor (measured) value less than 30 bar [435 psi]? | |
STEP 3G. Check for fuel rail pressure while cranking the engine. | Did Fault Code 2215 or Fault Code 559 become active during the failed start attempt? | |
STEP 3H. Check the fuel lift pump pressure. | Is the fuel lift pump pressure greater than the specifications outlined in Procedure 005-045? | |
STEP 4. | Fuel system troubleshooting procedures. | |
STEP 4A. Check for fault codes that pertain to the fuel system. | Did Fault Code 2215 or Fault Code 559 become active during the failed start attempt? | |
STEP 4B. Check for air in the high pressure pump fuel supply. | Is air present in the fuel supply? | |
STEP 4C. Measure the fuel inlet restriction. | Is the fuel inlet restriction above specification? | |
STEP 4D. Perform the single cylinder cutout test. | Can the miss or excessive smoke be attributed to a single cylinder? | |
STEP 4E. Perform the cylinder balance diagnostic test. | Does the cylinder performance test identify any cylinder that is contributing to a power imbalance? | |
STEP 4F. Measure the fuel drain line restriction. | Is the fuel drain line restriction within specification? | |
STEP 5. | Air handling troubleshooting procedures. | |
STEP 5A. Check the intake manifold pressure sensor accuracy. | Is the reading within 50.8 mm-Hg [2 in-Hg] of local barometric pressure? | |
STEP 5B. Check the air intake system for leaks. | Were any air intake system leaks found? | |
STEP 5C. Check the air intake restriction. | Is the air intake restriction greater than the specification? | |
STEP 5D. Inspect the turbocharger blades for damage. | Are the turbocharger blades damaged? | |
STEP 5E. Determine if the turbocharger is a wastegated turbocharger. | Is the turbocharger a wastegated turbocharger? | |
STEP 5F. Inspect the wastegate actuator hose. | Are holes or cracks found in the wastegate actuator hose? | |
STEP 5G. Inspect the turbocharger wastegate capsule for air leaks. | Did the wastegate actuator rod move? | |
STEP 5G-1. Inspect the turbocharger wastegate for proper operation. | ||
STEP 5G-2. Inspect the turbocharger wastegate for proper operation. | ||
STEP 5H. Measure turbocharger axial and radial clearance. | Are the axial and radial clearances within specification? | |
STEP 5I. Inspect the aftercooler. | Is the aftercooler free of cracks or other damage? | |
STEP 6. | Electronic feature troubleshooting procedures. | |
STEP 6A. Verify the throttle travel. | Does the throttle position read 0 when the throttle is released and 100 percent when the throttle is actuated? | |
STEP 6B. Check the ambient air pressure sensor accuracy. | Is the reading within 101.6 mm-Hg [4 in-Hg] of local barometric pressure? | |
STEP 6C. Check the intake manifold pressure sensor accuracy. | Is the reading within 101.6 mm-Hg [4 in-Hg] of local barometric pressure? | |
STEP 7. | Base engine troubleshooting procedures. | |
STEP 7A. Verify the overhead adjustments are correct. | Are the overhead settings within the reset limits? | |
STEP 7B. Check the exhaust restriction. | Is the exhaust system back pressure less than 127 mm-Hg [5 in-Hg] or 1763 mm-H 2O [68 in-H 2O] or 17 kPa [2.5 psi]? |
|
STEP 7C. Check the engine blowby. | Are the engine blowby measurements within specification? | |
STEP 7C-1. Verify turbocharger contribution to engine blowby. | ||
STEP 8. | Excessive vibration troubleshooting procedures. | |
STEP 8A. Check the gear ratio and propeller configuration. | Are the gear ratio and the propeller incorrectly matched to the engine power? | |
STEP 8B. Check for correct engine mounting isolators and for proper installation requirements. | Are the engine mount isolators correct and installed correctly? | |
STEP 8C. Check for damaged engine mounts and isolators. | Are the engine mounts and isolators in good condition? | |
STEP 8D. Check the exhaust system. | Is the exhaust system deficient? | |
STEP 8E. Check the engine driven accessories. | Is an engine driven accessory malfunctioning? | |
STEP 8F. Check the shaft coupling to gear coupling alignment. | Is the shaft coupling to gear coupling misaligned? | |
STEP 8G. Check the propeller shaft for proper installation. | Is the propeller shaft installed correctly? | |
STEP 8H. Check the propeller shaft for straightness. | Is the propeller shaft straightness within the OEM specification? | |
STEP 8I. Isolate the engine. | Does the engine vibration persist? | |
STEP 8J. Check for strut/cutlass bearing misalignment. | Is the strut/cutlass bearing misaligned or strut mounting not secure? | |
STEP 8K. Check the propeller. | Is the propeller out of balance or not fitted properly to the shaft? | |
STEP 8L. Check the V-angle on the V-strut. | Does the V-angle on the V-strut match the angle of the blade on the prop? | |
STEP 8M. Check the propeller tunnels. | Does the entry and exit of the propeller tunnel match with the propeller blades? | |
STEP 8N. Check the engine to transmission torsional coupling. | Is the torsional coupling incorrect or worn? | |
STEP 😯. Check the rudder. | Does the rudder have excessive in the rudder post? | |
STEP 8P. Check the engine flywheel housing to cylinder block alignment. | Is the flywheel housing alignment incorrect? |
Guided Step 1 – Perform basic troubleshooting procedures.
Guided Step 1A – Check for active fault codes or high counts of inactive fault codes. | |
---|---|
Conditions
ActionCheck for any active fault codes.
|
|
Active fault codes or high counts of inactive fault codes? |
|
YES | NO |
No Repair | |
Repair complete
|
Guided Step 1B – Perform basic troubleshooting checks. | |
---|---|
ConditionsNone. ActionVerify the following items.
|
|
Can the problem be verified? |
|
YES | NO |
No Repair |
The problem can |
Repair complete
|
Guided Step 1C – Perform the basic troubleshooting checks. | |
---|---|
ConditionsNone. ActionThe following items must be checked or verified before continuing.
|
|
All steps have been verified to be correct? |
|
YES | NO |
No Repair |
Correct the condition and verify the complaint is |
Repair complete
|
Guided Step 2 – Determination of engine symptom.
Guided Step 2A – Low power, poor acceleration, or poor response. | |
---|---|
ConditionsNone. ActionDetermine the engine symptom according to the engine performance. |
|
Is the engine symptom low power, poor acceleration, or poor response? |
|
YES | NO |
Perform the troubleshooting steps in the recommended order listed below.
|
No Repair |
Perform the troubleshooting steps suggested in the repair procedure.
|
Guided Step 2B – Engine misfire, engine speed surge, or engine speed unstable. | |
---|---|
ConditionsNone. ActionDetermine the engine symptom according to the engine performance. |
|
Is the engine symptom engine misfire, engine speed surge, or engine speed unstable? |
|
YES | NO |
Perform the troubleshooting steps in the recommended order listed below.
|
No Repair |
Perform the troubleshooting steps suggested in the repair procedure.
|
Guided Step 2C – Excessive white or black smoke. | |
---|---|
ConditionsNone. ActionDetermine the engine symptom according to the engine performance. |
|
Is the engine symptom excessive white or black smoke? |
|
YES | NO |
Perform the troubleshooting steps in the recommended order listed below.
|
No Repair |
Perform the troubleshooting steps suggested in the repair procedure.
|
Guided Step 2D – Low intake manifold pressure. | |
---|---|
ConditionsNone. ActionDetermine the engine symptom according to the engine performance. |
|
Is the engine symptom low boost pressure? |
|
YES | NO |
Perform the troubleshooting steps in the recommended order listed below.
|
No Repair |
Perform the troubleshooting steps suggested in the repair procedure.
|
Guided Step 2E – Engine will not start or difficult to start, engine shuts off unexpectedly. | |
---|---|
ConditionsNone. ActionDetermine the engine symptom according to the engine performance. |
|
Is the engine symptom engine will |
|
YES | NO |
Perform the troubleshooting steps in the recommended order listed below.
|
No Repair |
Perform the troubleshooting steps suggested in the repair procedure.
|
Guided Step 2F – Engine vibration excessive. | |
---|---|
ConditionsNone. ActionDetermine the engine symptom according to the engine performance. |
|
Is the symptom engine vibration is excessive occurring when the engine is in or out of gear? |
|
YES | NO |
Perform the troubleshooting steps in the recommended order listed below.
|
No Repair |
Perform the troubleshooting steps suggested in the repair procedure.
|
Return to the correct symptom tree.
|
Guided Step 3 – Engine starting and running troubleshooting procedures.
Guided Step 3A – Verify the fuel supply and return valves are open. | |
---|---|
Conditions
ActionVerify the fuel supply and return valves are in the open position. If the vessel is new or work has been completed on the vessel, the fuel valves could have been left in the OFF position. |
|
Is the fuel supply and return valves in the open position? |
|
YES | NO |
No Repair |
Turn the fuel supply and return valve to the OPEN position and verify that |
Guided Step 3A-1 – Check the fuel cooler for damage due to high fuel return back pressure. | |
---|---|
ConditionsNone. ActionRemove and inspect the fuel cooler. Check the fuel cooler for internal damage, or collapse. |
|
Is the fuel cooler damaged or collapsed internally? |
|
YES | NO |
Remove and replace the fuel cooler. |
No Repair |
Repair complete
|
Guided Step 3B – Verify the low pressure fuel lines are routed correctly. | |
---|---|
ConditionsNone. ActionIt is sometimes possible to get the low pressure fuel lines connected to the ECM cooling plate installed improperly. The top connection to the ECM cooling plate is the inlet and the bottom connection is the outlet. Verify these connections are correct if the low pressure fuel lines have been removed and reinstalled on the engine. |
|
Are the low pressure fuel lines connected properly to the ECM cooling plate? |
|
YES | NO |
No Repair |
Properly connect the low pressure fuel lines to the ECM cooling plate. The fuel inlet is the top connection. |
Repair complete
|
Guided Step 3C – Check the engine speed during cranking. | |
---|---|
Conditions
ActionUse INSITE™ electronic service tool to monitor Engine Speed while cranking the engine. If the engine does |
|
Is the engine cranking speed greater than 150 rpm? |
|
YES | NO |
No Repair |
Find and correct the cause for low cranking speed. Check the batteries, engine starting motor and accessory loads. See the troubleshooting symptom tree Engine Will Not Crank or Cranks Slowly. |
Repair complete
|
Guided Step 3D – Check the electronic control module (ECM) keyswitch voltage. | |
---|---|
Conditions
ActionMeasure the signal voltage.
Measure the keyswitch voltage with the keyswitch in the “ON” position and also with the keyswitch in the “Cranking” position. Refer to the wiring diagram for connector pin identification. |
|
Is the keyswitch voltage equal to the battery voltage? |
|
YES | NO |
No Repair |
Repair or replace the keyswitch harness, keyswitch, or check the battery connections. The keyswitch harness can be supplied by the OEM. |
Repair complete
|
Guided Step 3E – Check the ECM battery supply voltage. | |
---|---|
Conditions
ActionMeasure the voltage.
Measure the ECM voltage with the keyswitch in the “ON” position and also with the keyswitch in the “Cranking” position. Refer to the wiring diagram for connector pin identification. |
|
Is the ECM battery supply voltage equal to the battery voltage? |
|
YES | NO |
No Repair |
Repair or replace the ECM power harness. Check the battery connections and fuse terminals. |
Repair complete
|
Guided Step 3F – Verify the rail fuel pressure sensor accuracy. | |
---|---|
Conditions
ActionMonitor the rail fuel pressure sensor. Use INSITE™ electronic service tool, to monitor the rail fuel pressure sensor (measured) with the keyswitch ON and the engine OFF ( |
|
Is the rail fuel pressure sensor (measured) value less than 30 bar [435 psi]? |
|
YES | NO |
No Repair |
Replace the rail fuel pressure sensor. |
Repair complete
|
Guided Step 3G – Check for fuel rail pressure while cranking the engine. | |
---|---|
Conditions
ActionCheck for fuel rail pressure.
Attempting to start the engine for 30 continuous seconds allows the fault code logic time to run. If Fault Code 2215 or Fault Code 559 becomes active, then fuel rail pressure is If the engine starts during this attempt, it is possible that fuel prime to the high pressure pump has been lost. Look for loose fuel lines or filters that allow for loss of fuel prime. |
|
Did Fault Code 2215 or Fault Code 559 become active during the failed start attempt? |
|
YES | NO |
Follow troubleshooting Fault Codes 2215 or 559 Fuel Pump Delivery Pressure Low Choice. |
No Repair |
Repair complete
|
Guided Step 3H – Check the fuel lift pump pressure. | |
---|---|
Conditions
ActionInstall a pressure gauge at the inlet port of the fuel pump.
At initial key-on, the lift pump will run for 60 seconds then stop if the engine is not started and not operating. The lift pump will operate continuously once the engine is operating. |
|
Is the fuel lift pump pressure greater than the specifications? |
|
YES | NO |
Replace the fuel pump. |
Replace the fuel lift pump. |
Repair complete
|
Repair complete
|
Guided Step 4 – Fuel system troubleshooting procedures.
Guided Step 4A – Check for fault codes that pertain to the fuel system. | |
---|---|
Conditions
ActionCheck for fault codes.
Attempting to start the engine for 30 continuous seconds allows the fault code logic time to run. If Fault Code 2215 or Fault Code 559 becomes active, then fuel rail pressure is |
|
Did Fault Code 2215 or Fault Code 559 become active during the failed start attempt? |
|
YES | NO |
Follow troubleshooting Fault Code 559 Fuel Pump Delivery Pressure Low choice. |
No Repair |
Repair complete
|
Guided Step 4B – Check for air in the high pressure pump fuel supply. | |
---|---|
ConditionsNone. |
|
Is air present in the fuel supply? |
|
YES | NO |
Locate and correct the cause of air ingestion in the fuel supply system. Sources of air ingestion include loose fuel filters, loose fuel line fittings, loose or cracked fuel tank stand-pipes, or severe restrictions in the fuel supply lines and filters. |
No Repair |
Repair complete
|
Guided Step 4C – Measure the fuel inlet restriction. | |
---|---|
ConditionsNone. ActionMeasure the fuel inlet restriction at the customer connection. Maximum fuel inlet restriction at the customer connection
|
|
Is the fuel inlet restriction above specification? |
|
YES | NO |
Find and correct the cause of high fuel inlet restriction. Look for plugged OEM fuel filters or screens, a restricted ECM cooler, pinched OEM fuel lines, or a restricted stand pipe in the OEM fuel tank. |
No Repair |
Repair complete
|
Guided Step 4D – Perform the single cylinder cutout test. | |
---|---|
Conditions
ActionPerform the single cylinder cutout test.
|
|
Can the miss or excessive smoke be attributed to a single cylinder? |
|
YES | NO |
Look for a cause of the complaint, including valve lash and excessive crankcase pressure that can indicate power cylinder damage, or camshaft lobe wear. If no other damage is found, replace the fuel injector in the cylinder that was identified using the single cylinder cutout test. |
No Repair |
Repair complete
|
Guided Step 4E – Perform the cylinder balance diagnostic test. | |
---|---|
Conditions
ActionPerform the cylinder balance diagnostic test.
|
|
Does the Cylinder Performance Test identify any cylinder that is contributing to a power imbalance? |
|
YES | NO |
Look for a cause of the power imbalance, including valve lash and excessive crankcase pressure that may indicate power cylinder damage or camshaft lobe wear. If no other damage is found, replace the fuel injector in the cylinder contributing to the power imbalance. |
No Repair |
Repair complete
|
Guided Step 4F – Measure the fuel drain line restriction. | |
---|---|
ConditionsNone. |
|
Is the fuel drain line restriction within specification? |
|
YES | NO |
No Repair |
Look for causes of high drain line restriction, such as kinked or blocked fuel lines. |
Repair complete
|
Guided Step 5 – Air handling troubleshooting procedures.
Guided Step 5A – Check the intake manifold pressure sensor accuracy. | |
---|---|
Conditions
ActionMonitor the reading for intake manifold pressure with the engine off.
|
|
Is the intake manifold pressure reading less than 50.8 mm-Hg [2 in-Hg] of local barometric pressure? |
|
YES | NO |
No Repair |
Replace the intake manifold pressure sensor. |
Repair complete
|
Guided Step 5B – Check the air intake system for leaks. | |
---|---|
ConditionsNone. |
|
Were any air intake system leaks found? |
|
YES | NO |
Repair or replace the damaged component. |
No Repair |
Repair complete
|
Guided Step 5C – Check the air intake restriction. | |
---|---|
Conditions
ActionMeasure the intake system restriction. Maximum air intake restriction: Clean filter: 381 mm-H Dirty filter: 635 mm-H |
|
Is the air intake restriction greater than the specification? |
|
YES | NO |
Correct the cause of high intake air restriction. Check for plugged air filter or restricted air intake piping. |
No Repair |
Repair complete
|
Guided Step 5D – Inspect the turbocharger blades for damage. | |
---|---|
Conditions
ActionInspect the turbocharger.
|
|
Are the turbocharger blades damaged? |
|
YES | NO |
Replace the turbocharger assembly. |
No Repair |
Repair complete
|
Guided Step 5E – Determine if the turbocharger is a wastegated turbocharger. | |
---|---|
ConditionsNone. ActionDetermine if the turbocharger is a wastegated turbocharger. |
|
Is the turbocharger a wastegated turbocharger? |
|
YES | NO |
No Repair | No Repair |
Guided Step 5F – Inspect the wastegate actuator hose. | |
---|---|
Conditions
ActionInspect the integral wastegate actuator hose for cracks or holes. |
|
Are holes or cracks found in the wastegate actuator hose? |
|
YES | NO |
Replace the wastegate actuator hose. |
No Repair |
Repair complete
|
Guided Step 5G – Inspect the turbocharger wastegate capsule for air leaks | |
---|---|
Conditions
ActionPerform a leak test on the wastegate actuator capsule. Use Wastegate Pressure Test Kit, Part Number 3823799, to apply a regulated air supply of 59 in-Hg to the wastegate actuator capsule. No air should be heard (a leaking noise) through a functional wastegate capsule. |
|
Did the wastegate actuator capsule leak air? |
|
YES | NO |
Replace the wastegate actuator. |
No Repair |
Repair complete
|
Guided Step 5G-1 – Inspect the turbocharger wastegate for proper operation. | |
---|---|
Conditions
ActionCheck for wastegate actuator rod for movement. Use Wastegate Pressure Test Kit, Part Number 3823799, to apply a regulated air supply of [29 psi] to the wastegate actuator capsule. Check for wastegate actuator rod for movement. |
|
Did the wastegate actuator rod move? |
|
YES | NO |
No Repair | No Repair |
Guided Step 5G-2 – Inspect the turbocharger wastegate for proper operation. | |
---|---|
Conditions
ActionCheck for wastegate actuator rod movement with it disconnected from the turbocharger wastegate. Use Wastegate Pressure Test Kit, Part Number 3823799, to apply a regulated air supply of [29 psi] to the wastegate actuator capsule. Check for wastegate actuator rod for movement. |
|
Does the wastegate actuator rod move? |
|
YES | NO |
Move the wastegate lever back and forth and check for smooth operation. If the wastegate lever does |
Replace the wastegate actuator. |
Repair complete
|
Repair complete
|
Guided Step 5H – Measure turbocharger axial and radial clearance. | |
---|---|
Conditions
ActionFollow the procedure for measuring the axial and radial clearances of the turbocharger. |
|
Are the axial and radial clearances within specification? |
|
YES | NO |
No Repair |
Replace the turbocharger assembly. |
Repair complete
|
Guided Step 5I – Inspect the aftercooler. | |
---|---|
ConditionsNone. ActionInspect the aftercooler. |
|
Is the aftercooler free of cracks or other damage? |
|
YES | NO |
No Repair |
Repair or replace the aftercooler assembly. |
Repair complete
|
Guided Step 6 – Electronic feature troubleshooting procedures.
Guided Step 6A – Verify the throttle travel. | |
---|---|
Conditions
ActionVerify the throttle travel.
|
|
Does the throttle position read 0 when the throttle is released and 100 percent when the throttle is actuated? |
|
YES | NO |
No Repair |
Determine and correct the cause of the throttle lever restriction. |
Repair complete
|
Guided Step 7 – Base engine troubleshooting procedures
Guided Step 7A – Verify the overhead adjustments are correct. | |
---|---|
Conditions
ActionMeasure the overhead settings.
|
|
Are the overhead settings within the reset limits? |
|
YES | NO |
No Repair |
Adjust the overhead settings. |
Repair complete
|
Guided Step 7B – Check the exhaust restriction. | |
---|---|
ConditionsNone. ActionInstall a pressure gauge into the exhaust system just past the turbocharger outlet to check the exhaust system back pressure. |
|
Is the exhaust system back pressure less than 127 mm-Hg [5 in-Hg] or 1763 mm-H |
|
YES | NO |
No Repair |
Fix or clear the source of high exhaust system restriction. |
Repair complete
|
Guided Step 7C – Check the engine blowby. | |
---|---|
ConditionsNone. |
|
Are the engine blowby measurements within specification? |
|
YES | NO |
No Repair | No Repair |
Return to step 2, or contact a local Cummins® Authorized Repair Location for further diagnostic and troubleshooting instructions.
|
Guided Step 8 – Excessive vibration troubleshooting procedures.
Guided Step 8A – Check the gear ratio and propeller configuration. | |
---|---|
Conditions
ActionCheck for an incorrect matching of the gear ratio and propeller to the engine power. |
|
Are the gear ratio and the propeller incorrectly matched to the engine power? |
|
YES | NO |
Contact a Cummins® Distributor or Marine District Field Service Manager. |
No Repair |
Repair complete
|
Guided Step 8B – Check for the correct engine mounting isolators and for proper installation requirements. | |
---|---|
ConditionsNone. ActionCheck for the correct engine mount isolators and for propeller installation requirements. |
|
Are the engine mount isolators correct and installed correctly? |
|
YES | NO |
No Repair |
Check for proper isolator installation requirements. Replace and repair vibration isolators as needed. |
Repair complete
|
Guided Step 8C – Check for damaged engine mounts and isolators. | |
---|---|
ConditionsNone. ActionInspect the engine mount and isolators for failure. |
|
Are the engine mounts and isolators in good condition? |
|
YES | NO |
No Repair |
Remove and replace the engine mount isolators. |
Repair complete
|
Guided Step 8D – Check the exhaust system. | |
---|---|
ConditionsNone. ActionCheck for exhaust system deficiencies. |
|
Is the exhaust system deficient? |
|
YES | NO |
Repair or replace as needed. See the Exhaust System section in the Marine Recreational Installation Directions, Bulletin 3884649 and the OEM service literature and instructions. |
No Repair |
Repair complete
|
CAUTION
Some sea water pumps are belt driven. Operating the engine when the sea water pump is disconnected can result in engine damage due to overheating. |
Guided Step 8E – Check the engine driven accessories. | |
---|---|
Conditions
ActionCheck for engine driven accessories malfunctions. Isolate or disconnect the accessories and check for vibration. Do |
|
Is an engine driven accessory malfunctioning? |
|
YES | NO |
Determine the cause of the malfunctioning accessories and correct the problem. See the Engine Driven Accessories section in the Marine Recreational Installation Directions, Bulletin 3884649. If the accessory is |
No Repair |
Repair complete
|
Guided Step 8F – Check the shaft coupling to gear coupling alignment. | |
---|---|
Conditions
ActionCheck the shaft coupling to gear coupling alignment. |
|
Is the shaft coupling to gear coupling misaligned? |
|
YES | NO |
No Repair | |
Repair complete
|
Guided Step 8G – Check the propeller shaft for proper installation. | |
---|---|
ConditionsNone. ActionCheck the propeller shaft for proper installation. |
|
Is the propeller shaft installed correctly? |
|
YES | NO |
No Repair | |
Repair complete
|
Guided Step 8H – Check the propeller shaft for straightness. | |
---|---|
ConditionsNone. ActionCheck the propeller shaft for straightness. |
|
Is the propeller shaft straightness within the OEM specification? |
|
YES | NO |
No Repair |
Repair or replace the propeller shaft as needed. Refer to an authorized OEM Service Location. |
Repair complete
|
Guided Step 8I – Isolate the engine. | |
---|---|
Conditions
ActionRun the engine without the drive shaft attached at the coupler. |
|
Does the engine vibration persist? |
|
YES | NO |
Check the engine vibration damper for damage. Repair or replace as needed. |
No Repair |
Repair complete
|
Guided Step 8J – Check for strut/cutlass bearing misalignment. | |
---|---|
Conditions
ActionCheck for strut/cutlass bearing misalignment or strut mounting is not secure. |
|
Is the strut/cutlass bearing misaligned or strut mounting |
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YES | NO |
Check the strut for mounting stiffness. Repair or replace as needed. Refer to an authorized OEM Service Location. |
No Repair |
Repair complete
|
Guided Step 8K – Check the propeller. | |
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ConditionsNone. ActionCheck for propeller out-of-balance or propeller not fitted properly to shaft. |
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Is the propeller out of balance or |
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YES | NO |
Check the propeller for accuracy. Repair or replace as needed. Refer to an authorized OEM Service Location. |
No Repair |
Repair complete
|
Guided Step 8L – Check the V-angle on the V-strut. | |
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ConditionsNone. ActionCheck to see if the V-angle on the V-strut does not match the angle of the blade on the prop. |
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Does the V-angle on the V-strut match the angle of the blade on the prop? |
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YES | NO |
No Repair |
Repair or replace as needed. Refer to an authorized OEM Service Location. |
Repair complete
|
Guided Step 8M – Check the propeller tunnels. | |
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ConditionsNone. ActionCheck if the propeller tunnels are properly matched with the propellers. |
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Does the entry and exit of the propeller tunnel match with the propeller blades? |
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YES | NO |
No Repair |
Repair or replace as needed. Refer to an authorized OEM Service Location. |
Repair complete
|
Guided Step 8N – Check the engine to transmission torsional coupling. | |
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ConditionsNone. ActionCheck for incorrect or worn torsional coupling. |
|
Is the torsional coupling incorrect or worn? |
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YES | NO |
Replace the coupling. Refer to the OEM service literature. |
No Repair |
Repair complete
|
Guided Step 😯 – Check the rudder. | |
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ConditionsNone. ActionCheck the rudder for excessive play in the rudder post. |
|
Does the rudder have excessive play in the rudder post? |
|
YES | NO |
Repair or replace as needed. Refer to an authorized OEM Service Location. |
No Repair |
Repair complete
|