40 hp only going 1/4 speed when wide open

[Biggen]

I have a 40 hp tracker motor, made by mercury, One day it started idleing very low and cutting off when i tried to engage it into gear. Once i got it into gear it only went about 1/4 of the speed it usually does. In neutral it seemed to rev fine, but when in gear, the rpms werent high at all. I looked at the carb thinking it wasnt opening all the w2ay, but it did when the boat was on gear at Wide open throttle. Any suggestions? Fouled plug? Thanks

 

[RICKRICK1]

Re: 40 hp only going 1/4 speed when wide open

Check cylinder compression. Check for spark, check fuel system for sucking air. Overhaul carbs.

 

[Biggen]

Re: 40 hp only going 1/4 speed when wide open

Do those problems you have listed come overnight or do they gradually get worse, I was hoping since it happened all of a sudden it would probably be something less severe than loss of cylinder comp or a fule pump problem.?

 

[Biggen]

Re: 40 hp only going 1/4 speed when wide open

would a cylinder lose compression all of a sudden or would it be gradual. Im guessing at this point it may be a head gasket, i cleaned the plugs and it still isnt running right.

 

[The Marine Doctor]

Re: 40 hp only going 1/4 speed when wide open

Biggen..you engine does not have a head.<br /><br />Yes it is possible that the engine lost compression immediately.<br /><br />TMD