Engine runs great in neutral, bogs down in gear under load

[SolomonCraig]

My 25 hp Tohatsu 4-stroke has just recently been having a lot of problems when put in gear. Out of the water in gear it revs high and runs fine, which is the same with it in neutral in/out of water. Everything seems perfect until about 1/3 of the throttle where the power quits increasing. I've taken apart and cleaned the carb as well as replaced spark plugs and fuel filter. I know there has been similar posts about this problem but I've seemed to read them all and can't get anywhere. I've thought about the adjusting the floats?? The boat ran fine the first couple times out this season then out of nowhere in the middle of lake it dropped rpm's and has been giving us problems since. Really appreciate any help I can get.

 

[matt88]

Re: Engine runs great in neutral, bogs down in gear under load

has it been overheating? Had a friend who had the same problem with his outboard and he had a blown head gasket.

 

[pvanv]

Re: Engine runs great in neutral, bogs down in gear under load

What model?

 

[SolomonCraig]

Re: Engine runs great in neutral, bogs down in gear under load

I'll check the head gasket but I would have thought a blown head gasket would effect it in neutral more.... It's the MSF25A. The thing that really gets to me is that it runs perfect up until higher loads....and that it is constant...no variance?

 

[pvanv]

Re: Engine runs great in neutral, bogs down in gear under load

The MFS25A has 3 carbs. They all need to be in good shape. First, I would confirm the crankcase oil level is not even a hair high, then re-check and clean all 3 carbs, and finally do a compression test. These motors do not blow head gaskets very often.

Does the engine seem to misfire, of just not make enough power? The latter is typical of an overfilled crankcase.

 

[Tohatsuguy9]

Do you ever get the problem resolved?

 

[Tohatsuguy9]

*did

 

[GA_Boater]

Do you ever get the problem resolved?

You're expecting an answer from an OP who left over 11 years ago? You started a thread, so don't ask in old threads.

Closed.