Engine Runs Erratically; Performance Loss; Battery Will Not Hold Charge - Mercury 9.9 EH 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.
• Engine fuel filter is obstructed. Refer to Maintenance
section.
• Fuel tank filter obstructed.
• Stuck anti‑siphon valve on built in fuel tank.
• Fuel line is kinked or pinched.
• Fuel pump failure.
• Ignition system component failure.

Performance Loss

POSSIBLE CAUSES
• Throttle not fully open.
• Damaged or improper size propeller.
• Incorrect engine timing, adjustments, or setup.
• Boat overloaded or load improperly distributed.
• Excessive water in bilge.
• Boat bottom is dirty or damaged.

Battery Will Not Hold Charge

POSSIBLE CAUSES
• Battery connections are loose or corroded.
• Low electrolyte level in battery.
• Worn out or inefficient battery.
• Excessive use of electrical accessories.
• Defective rectifier, alternator, or voltage regulator.
TROUBLESHOOTING
100