Re: Best years for OMC 10 horse?

[frankr]

quote ShoestringMariner:

quote FrankR:

In my not-so-humble opinion, eliminating the powerhead pulling requirement was the worst thing they ever did to that series. Sure it made it easy, but it also eliminated the requirement to at least look at the crankshaft carbon seal. One of the biggest causes of thrown rods, even though most people blame it on the oil.

Frank, any chance you would mind elaborating on this? It sounds like an interesting and important tidbit for newbs to understand, this one included.

Actually, I figure I’ve said it so many times people are sick of hearing me. And I’m sure some don’t believe it anyway. But here goes, one more time. That seal keeps water out of the crankcase. The oiling system actually then pumps it throughout the crankcase. Not a lot of water like what would cause poor running, but enough water to cause bearing wear. And worse yet rust of the crank journals in storage. When you start it up, that rust scours and scrapes at the rod bearings. Remember the "bearing" is a thin coat of silver plating, prior to the needle bearing rods.

I keep preaching that the seal needs to be in 100% condition and always replace the 303347 o-ring and 303355 gasket whenever it is apart.