1978 402 starter trouble

[mercury 402]

I purchased a 402 Mercury motor and the starter mounting was broken away from the block. all the pieces were there so I had a very good aluminum welder repair the break. now, I can see the starter drive just barely meshes with the flywheel teeth and I'm thinking the binding is what broke the block out where the starter mounts. Now... I have a 9 tooth starter drive and I'm wondering if maybe the previous owner put the wrong drive on and that caused the break? if I put a 10 tooth drive on, will that correct the problem. I bought the motor from an old guy that has no memory of why they quit using it, so he can't remember what work was done either. serial 4862453 and the date code on starter is June of 1977, which I'm thinking could be the original??

[boats.net]

Not think the 10 tooth will align with teeth on flywheel but I never tried it.