I add SeaFoam to my crankcase before I change oil. I add it and take the boat out for the day and change oil when I return. I've read that it helps to clean the motor and lubricate the top end.

Does anyone else do this?
Does anyone see any downside or ill-effects?

O don't know about in your crankcase, but I treat my leftover gas with it before running the engine in the fall to warm the engine up for winterizing.

Ive added it to the cranck case before...but never ran the engine other then at idle for a little while to fully warm up and then change oil....isnt there something about not driving the engine on the bottle? or am i getting confused with some other engine flush product?
But i use sea-foam for cleaning out carbon deposits on all my motorised stuff....works liek a charm

I've used it for cleaning out the engine...Haven't spent the day boating with it though. Also like pouring it down the intake while running to kill the bugs around the marina

My F&I guy told me about this stuff. He also told me it works great in motorcycles if there is a little crap in the carbs. Any body use it in there cycles?

John S.

Use it in my bike every spring, and it worked wonders for my ol' outboard. Of course, this was in the fuel.