Section 6 - Troubleshooting
Diagnosing Electronically Controlled Fuel System Problems
A Mercury Diesel authorized repair facility has the proper service tools for diagnosing problems on electronically controlled fuel
systems. The engine control module (ECM) on these engines has the ability to detect problems with the system when they
occur, and store a trouble code in the ECM's memory. This code can then be read later by a service technician using a special
diagnostic tool.
Troubleshooting Charts
Starter Motor Will Not Crank Engine, or Cranks Slow
Possible Cause
Battery switch turned off.
Remote control not in neutral position.
Open circuit breaker or blown fuse.
Loose or dirty electrical connections or damaged wiring.
Bad battery.
Engine Will Not Start, or Is Hard to Start
Possible Cause
Lanyard stop switch activated.
Improper starting procedure.
Empty fuel tank or fuel shut‑off valve closed. Fill tank or open valve.
Throttle not operating properly.
Faulty electrical stop‑circuit.
Clogged fuel filters.
Stale or contaminated fuel.
Fuel line or tank vent line kinked or clogged.
Air in fuel injection system.
Faulty wire connections.
Electronic fuel system fault.
Engine Runs Rough, Misses, or Backfires
Possible Cause
Throttle not operating properly.
Idle speed too low.
Clogged fuel or air filters.
Stale or contaminated fuel.
Kinked or clogged fuel line or fuel tank vent line.
Air in fuel system.
Electronic fuel system faulty.
Poor Performance
Possible Cause
Throttle not fully open.
Damaged or improper propeller.
Excessive bilge water.
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Turn switch on.
Position control lever in neutral.
Check and reset circuit breaker or replace fuse.
Check all electrical connections and wires (especially battery
cables). Clean and tighten faulty connection.
Test and replace if bad.
Check lanyard stop switch.
Read starting procedure.
Check the throttle for freedom of movement.
Have a Mercury Diesel authorized repair facility service the electrical stop
circuit.
Replace fuel filters.
Drain tank. Fill with fresh fuel.
Replace kinked lines or blow out the lines with compressed air to remove
obstruction.
Purge fuel injection system.
Check wire connections.
Have the electronic fuel system checked by a Mercury Diesel authorized repair
facility.
Check the throttle for binding or an obstruction.
Have idle speed checked and adjusted by a Mercury Diesel authorized
repair facility.
Replace fuel or air filters.
If fuel is contaminated, drain tank. Fill with fresh fuel.
Replace kinked lines or blow out lines with compressed air to remove
obstruction.
Purge fuel injection system.
Have electronic system checked by a Mercury Diesel authorized repair
facility.
Inspect throttle cable and linkages for proper operation.
Replace propeller. See a Mercury Diesel authorized repair facility.
Drain and check for cause of entry.
Remedy
Remedy
Remedy
Remedy
90-8M0113988
eng
DECEMBER 2015