Re: 3cyl 65-70-75 OMC Rebuild

[DAN ANDERSON]

The motor finally picked up the revised sleeve in 1994 I believe. It was an oval exhaust port at that point and corrected the problem. All of the fixes were in by then. The water pump kit was the main fix, but moving the overboard elbow was a good way to make sure the block was full of water at all times (vs air locked). They later came out (by 1994) a thicker exhaust side cover. That allowed deeper support ribs which in turn allowed more water to pass by the exhaust chamber. This stopped the scuffing of the piston skirts. Especially the top pistons which combined with the block air locking. You have to think of combined problems. John I feel for you on problems/updates that can be seen from outside in regards to running motors in stock classes. Doesn’t matter if the engines don’t run well that way or won’t last. Especially racing! Maybe my engine builder will have a copy of the bulletin. We sent it out with every motor block we modified so the dealer could do the rest of the stuff to the motor.

Dan in TN