Engine Runs Rough, Misses, Or Backfires; Poor Performance; Troubleshooting Charts Specifically For 3.0 Tks; Starter Motor Will Not Crank Engine, Or Cranks Slow - Mercury 3.0 MPI ECT Operation & Maintenance Manual

Engine Runs Rough, Misses, or Backfires

Possible Cause
Clogged fuel filter.
Stale or contaminated fuel.
Kinked or clogged fuel line or fuel tank vent line.
Flame arrestor dirty.
Faulty ignition system component.
Idle speed too low.
EFI system fault.

Poor Performance

Possible Cause
Throttle not fully open.
Damaged or improper propeller.
Excessive bilge water.
Boat overloaded or load improperly distributed.
Flame arrestor dirty.
Boat bottom fouled or damaged.
Ignition problem.
Engine overheating.
EFI system fault.

Troubleshooting Charts Specifically for 3.0 TKS

Starter Motor Will Not Crank Engine, or Cranks Slow

Possible Cause
Battery switch turned off.
Remote control not in the neutral position.
Open circuit breaker or blown fuse.
Loose or dirty electrical connections or damaged
wiring.
Bad battery or low battery voltage.
Lanyard stop switch activated.

Engine Will Not Start or Is Hard to Start

Possible Cause
Lanyard stop switch activated.
Improper starting procedure.
Insufficient fuel supply.
Engine flooded.
Faulty ignition system component.
Clogged fuel filter.
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Replace filter.
Drain fuel tank. Fill with fresh fuel.
Replace kinked lines or blow out lines with compressed air to remove
obstruction.
Clean the flame arrestor.
Service ignition system.
Have EFI system checked by an authorized Mercury MerCruiser dealer.
Have EFI system checked by an authorized Mercury MerCruiser dealer.
Inspect the throttle cable and linkages for proper operation.
Replace the propeller.
Drain and check for cause of entry.
Reduce load or redistribute load more evenly.
Clean the flame arrestor.
Clean or repair as necessary.
See Engine Runs Rough, Misses, or Backfires.
See Excessive Engine Temperature.
Have EFI system checked by an authorized Mercury MerCruiser dealer.
Turn the switch on.
Position the control lever in neutral.
Check and reset the circuit breaker or replace fuse.
Check all electrical connections and wires (especially battery cables).
Clean and tighten all faulty connections.
Test the battery and charge if necessary; replace if bad.
Check the lanyard stop switch.
Check the lanyard stop switch.
Read the starting procedure.
Fill fuel tank or open valve.
Turn the key switch off and wait five minutes. Push the throttle only button,
push the remote control handle/throttle lever to the 1/4 throttle position, and
attempt to restart.
Service the ignition system.
Replace fuel filter.
Section 6 - Troubleshooting
Remedy
Remedy
Remedy
Remedy
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