Mercury 25 hp dies at 1/2 throttle

[Onyx8234]

I have a 1988 mercury 25 hp that dies at above half throttle. When the engine quits it has to sit for around an hour before its possible to restart it. The fuel bulb still has pressure when the engine dies. If I'm quick enough to throttle down it just sputters then runs normal. I've checked the canister fuel filter and it's still full of fuel and the filter element looks good. Could it possibly be getting too much fuel at higher rpms and flooding it? The hour wait time before being able to restart is what has me stumped. Any help would be appreciated.

 

[flyingscott]

Do a compression and spark test? Will the engine run for any period of time below 1/2 throttle? The ball should not be hard after it runs and the filter should not be full. Has any Carb work been done recently? Does pumping the primer help it run better or not.

 

[Onyx8234]

The engine seems to run fine below half throttle. No carb work that I'm aware of, I've only owned the boat a few months. Once the engine dies, nothing seems to help get it started back. Pumping the bulb does nothing to help once it starts sputtering

 

[ondarvr]

You need to check for spark when it won't start.

 

[flyingscott]

Disconnect the kill switch from the switch box and see if that makes a difference.

 

[Onyx8234]

OK after some more trial and error, it looks like the carb. I replaced the spark plugs which were very gas saturated. It's sparking at least 3/8 so the coils seem fine. Took the boat to the lake and it ran fine. I shut the engine off for about 30 minutes and it wouldn't start back. Pulled the new plugs and they were gas covered again. Dried them off and it fired up. Thinking the float in the carb is sticking.