96' 75hp Exhaust Manifold Leaking?

[jpbaker]

I currently have a '96' 75hp Force motor and am experiencing (burnt) oil residue inside the lower cowling. The residue seems to be showing up on the right side (looking from the back) under the exhaust plate. Now my question is, how can I be sure that this is the problem, and not the powerhead gasket on that side?? Also for further info, I did a compression check and all 3 cylinders are 120lbs accross the board. The exhaust plate in question is about 6" wide and extends the lenght of the motor down the side. Anyone with experience with this problem, please feel free to comment.

 

[12Footer]

Re: 96' 75hp Exhaust Manifold Leaking?

Welcome to iboats, coachman.<br />The deposits you are seeing is carbon and unburnt fuel. One or more cylinders is probably burrning too rich.<br />But understand, carbon buildup is normal, and needs to be "cleaned-out" every 80 hours or so, and half that time (40hours), if you spend most of the time idling, or low throttle.<br />The compression is fine, so i would suspect the gaskets are too.(you would probably see a leak-down if not).<br />And my advice would be to just let it burn too rich. You can decarbon more frewquently, and carry spare plugs....because burning too lean is death to 2cycle outboards.Err on the side of adequate protection.

 

[jpbaker]

Re: 96' 75hp Exhaust Manifold Leaking?

Thanks, I do alot of trolling, and always power up after several hrs. or so. guess it could also use a good cleaning with some deep creep or seafoam which ever would work best. I do seem to have some leakage just under the exhaust plate, so I guess its' time for a set of gaskets on there.

 

[roscoe]

Re: 96' 75hp Exhaust Manifold Leaking?

Yep, replace them.<br />Carbon buildup is normal for the midsection and lower unit, but not for the cowling engine compartment.