How to Troubleshoot a Mercury Outboard 50 HP
- 1). Check the spark plug for excessive dirt and corrosion. If the plug is a gray hue in color, this usually indicates that it is good. Clean or replace the spark plug if necessary.
- 2). Inspect the rubber fuel-primer bulb to check that it is pliable when squeezed. If you feel resistance, sufficient fuel may not be reaching the engine. Have a qualified marine mechanic check to see if the fuel assembly needs to be replaced. Ensure that there is enough fuel in the tank. Inspect all the fuel lines for leaks.
- 3). Use a plastic squirt bottle to pour a small amount of fuel-and-oil mix directly into the carburetor intake if your Mercury 50 HP outboard engine does not turn over. Pull the starter cord right after pouring the fuel and oil into the engine.
- 4). Inspect the seals, or gaskets, between the power head and fuel pump for any damage or cracks. The gaskets are roughly 1/8 inch thick and they seal the fluids in the engine. If they are compromised, they could allow air into the system and create a vacuum leak. Have a mechanic replace the gaskets, if necessary.
- 5). Remove the plastic engine cowling to see if there is oil residue on the inside of the cover. If there is evidence of oil leakage, it could indicate that the rings are bad. Have a marine mechanic investigate this further for you.
- 6). Replace the fuel pump cover if it is damaged or cracked. A cracked cover could also allow air into the system and create a vacuum when priming the fuel bulb.
- 7). Remove the fuel pump screws and prime the fuel bulb to check for leaks. If there is a small amount of fuel leaking from the hole at the rear of the pump, the diaphragm may need to be replaced.
- 8). Check the system for adequate pressure. Remove the spark plug and attach the compression test gauge. A normal reading should be between 60 psi and 90 psi. If the reading is not within this range, it could indicate that the rings are worn. Have a marine mechanic investigate further for you.
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