Troubleshooting; Engine Will Not Start; Engine Runs Erratically - Mercury jet 20 Manual

Engine Will Not Start

POSSIBLE CAUSES
• Lanyard stop switch not in "RUN" position.
• Incorrect starting procedure. Refer to Operation section.
• Old or contaminated gasoline.
• Engine flooded. Refer to Operation section.
• Fuel is not reaching the engine.
a. Fuel tank is empty.
b. Fuel tank vent not open or restricted.
c. Fuel line is disconnected or kinked.
d. Primer bulb not squeezed.
e. Primer bulb check valve is faulty.
f. Fuel filter is obstructed. Refer to Maintenance section.
g. Fuel pump failure.
h. Fuel tank filter obstructed.
• Ignition system component failure.
• Spark plugs fouled or defective. Refer to Maintenance section.

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.
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.
• Blockage of the water intake.

TROUBLESHOOTING

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