info

[daveski1964]

I have a 1986 85 hp force motor ,,carbs need rebuild ,I check compression have 100lbs in top two cylinders and 90lbs in bottom cylinder,,my question, is that enough compression to get thru this fishing season and I could rebuild motor over winter??I was going to rebuild carbs and see if boat would make it thru this fishing season......should I press my luck or no....just rebuild now???

 

[Frank Acampora]

Re: info

100 PSI is low, but if the engine starts and runs well, it is not the end of the world. 90 and 100 psi will reduce engine horsepower but it is certainly not a reason to automatically rebuild or swap powerheads.

Piston rings just don't wear on these outboards because 1. They get a fresh shot of oil each revolution and 2. They just don't get the hours of running time necessary to wear.

More likely, one or more rings on each piston is sticking in the groove letting compression pressure past them. Before doing anything else, re-check compression with another gauge to ensure accuracy. Then, if it is still low, a decarb treatment might help.

 

[daveski1964]

Re: info

100 PSI is low, but if the engine starts and runs well, it is not the end of the world. 90 and 100 psi will reduce engine horsepower but it is certainly not a reason to automatically rebuild or swap powerheads.

Piston rings just don't wear on these outboards because 1. They get a fresh shot of oil each revolution and 2. They just don't get the hours of running time necessary to wear.

More likely, one or more rings on each piston is sticking in the groove letting compression pressure past them. Before doing anything else, re-check compression with another gauge to ensure accuracy. Then, if it is still low, a decarb treatment might help.

I will give this I try thank you MR Frank