Mercury Jet 20 Manual page 92

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3 – 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 anti-siphon valve located on permanently built in type fuel tanks.
d. Fuel line is kinked or pinched.
•
Fuel pump failure.
•
Ignition system component failure.
4 – ENGINE OVER-SPEED (EXCESSIVE RPM)
POSSIBLE CAUSES
•
Outboard mounted too high on the transom.
•
Worn jet pump impeller or liner.
•
Incorrect jet pump impeller clearance adjustment.
•
Tilting the outboard out beyond a vertical position.
•
Cavitation of the impeller due to rough water or obstruction in the boat hull.
5 – 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
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