Reply To: OMC serial number

[Don]

Dale wrote:

I pulled the transfer covers off this afternoon. I found a stuck ring on one of the two ring pistons, and a score on the intake side of that piston. After a little carbon scratch’en I found where the gas/oil mix goes from the carburetor, right into the exhaust. Why did those engineers do that? Makes no sense to me. I think I am gonna block that port off completely.

thanks guys n Happy New Year!

Not sure what you are questioning here. Are you saying that this recirc/dump system caused the stuck ring and scoring? I’m not that familiar with this initial step toward an overboard drainless system. I guess the engineers were hoping that dumping the excess puddling fuel/oil mix into the hot exhaust housing/chamber would ignite that mix and burn it off. I really don’t see much difference in this initial step and the drain system used before. Prior years dumped excess puddling fuel/oil into the exhaust housing through internal passages in the crankcase. This system seems to do the same thing, it is just more obvious. Perhaps this system was a “cost savings” over prior systems with the internal machined passages…. Who knows, just guessing.
But, I do know that if you block the exit passage for the puddling fuel/oil to escape, the engine will surely “load up” at idle and probably foul plugs. I really don’t think this system had anything to do with the stuck ring/scoring. I suppose you could install one of those nipples into the upper bypass cover and reroute the drain to there, I don’t recommend it though. These were the last 22CI engines that idled nicely. The 1971 drainless system brought degraded idle quality and plug fouling issues.