Home › Forum › Ask A Member › ’57 35hp flywheel compatibilities › Re: ’57 35hp flywheel compatibilities
Im with FranR. The short/small key is #307480. That is the most common key OMC uses on all motors. Still used today on 300hp G2 motors. The #302602 long key (used on the ’57 & others) is the oddball. NEVER rely on a cast number to get the same part. Especially when it is a rotating assembly. As the service bulletin points out a different hub was cast into the same outer part of the flywheel.
If you take the key out of the crank does the flywheel drop down far enough onto the crank? (You mentioned it was seating up a 1/4" too high?) Even if it does I would not feel comfortable using this flywheel on the motor. I mentioned before that OMC had some balance issues with these motors as horsepower went up. The 40hp was a tipping point. They had to go in & make the top of the crank bigger, but I suspect other things happened to stop the harmonics of the engine from fretting the crank to flywheel fit. Just my opinion, but I did hear it discussed. Other motors had some of these problems during my tenure at OMC.
Dan in TN