50 hp jhonson limping

[cooterdude]

hey guys i have a 50 hp jhonson on my 28 ft pontoon boat
it starts up and runs fine for about 30 minutes then it seems
to go into a limp mode with about half its horsepower
am i overloading the engine trying to push my barge
or is there something else i can look for to help the problem

 

[bktheking]

Re: 50 hp jhonson limping

After 30 minutes check for spark on both cylinders, could be losing spark from the heat, could be a bad coil.

 

[Silvertip]

Re: 50 hp jhonson limping

Or a failing ignitiion module. Does the alarm system beep when you first turn the key on? If not, you may have an overheat conditon that you don't know about and the engine is trying to protect itself by going into SAFE mode which limits RPM to about 2500 RPM.

 

[bktheking]

Re: 50 hp jhonson limping

Another bit of info would be the year?