Engine Runs Erratically; Performance Loss; Warning Horn Activates (With Power Loss) - Mercury 225 Manual

Engine Runs Erratically

POSSIBLE CAUSES
•
Spark plugs fouled or defective. Refer to Maintenance
section.
• Incorrect setup and adjustments.
• Fuel is being restricted to the engine.
a. Engine fuel filter is obstructed. Refer to Maintenance
section.
b. Fuel tank filter obstructed.
c. Stuck antisiphon valve on built‑in fuel tank.
d. Fuel line is kinked or pinched.
e. Injector plugged.
• Threaded connection of an air hose is loose.
• Fuel pump failure.
• Ignition system component failure.

Performance Loss

POSSIBLE CAUSES
• Throttle not opening fully.
• Damaged propeller or improper propeller size.
• Boat overloaded or load improperly distributed.
• Excessive water in bilge.
• Boat bottom is dirty or damaged.
• Warning horn failure.
• Engine block pressure sensor or coolant temperature sensor
failure (Guardian is activated).
• Restricted fuel system or filter (loss of fuel or air pressure).

Warning Horn Activates (With Power Loss)

POSSIBLE CAUSES
• Intermittent horn sound:
TROUBLESHOOTING
100
eng