Troubleshooting; Starter Motor Will Not Crank The Engine; Engine Will Not Start; Engine Runs Erratically - Mercury 300R HD CMS Mechanical Operation And Maintenance Manual

Starter Motor Will Not Crank the Engine

POSSIBLE CAUSES
• Lanyard stop switch not in RUN position.
•
Open 20‑amp fuse. Check the power driver fuse. Refer to Maintenance
section.
• Outboard is not shifted to neutral position.
• Weak battery or battery connections are loose or corroded.
• Ignition key switch failure.
• Wiring or electrical connection faulty.
• Starter motor solenoid or starter relay failure.

Engine Will Not Start

POSSIBLE CAUSES
•
Incorrect starting procedure. Refer to Operation section.
• Old or contaminated gasoline.
• Fuel is not reaching the engine.
• Fuel tank is empty.
• Fuel tank vent not open or restricted.
• Fuel line is disconnected or kinked.
• Fuel filter is obstructed. Refer to Maintenance section.
• Fuel pump failure.
• Fuel tank filter obstructed.
• Ignition system component failure.
•
Spark plugs fouled or defective. Refer to Maintenance section.

Engine Runs Erratically

POSSIBLE CAUSES
• Overheating ‑ Warning horn not working.
• Low oil pressure. Check oil level.
•
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 located on permanently built‑in type fuel tanks.
d. Fuel line is kinked or pinched.
• Fuel pump failure.
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TROUBLESHOOTING

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