Home › Forum › Ask A Member › Mercruiser starter. › Re: Mercruiser starter.
I had the same issue on a replacement starter on my 58 35johnson. Different starter but same issue. It was in fact the drive gear dragging every now and then on the flywheel ring gear. In my case I had to shim it "down" so the drive gear sat lower under the flywheel when at the resting position.
Bet you will need to do the same on yours. I finally found the issue when I was watching the motor with the cover off and saw a few sparks from the clash.
A friend who works on vintage cars told me about shimming and that it was not that uncommon of a need on older motors with new staters. You can get shim sheet stock from McMaster and cut it with tin snips to make a shim between the top bracket of the Sartre and the motor body to push it away from the flywheel
Hope this helps good luck