My Dad just had a motor freshened up, because; It had a blown head gasket and I guess water was getting in the cylinders and the motor would not start. He had his started checked out before reinstalling the motor and it was good.
When he went to start the motor in the boat he got it to start a few times initially but then the starter began to grind and eventually got stuck on the flywheel. He installed a new high torque starter and it pretty much did the same thing. So he got a new marine mini starter. The motor started a few more times and he got everything set up. So he went out the next day and it was gringding again and not turning the motor over.
This is all info I am receiving from my Dad, I have not been involved physically. I am going to give him a hand Sunday and wanted to see if anyone had any experience with this problem.

My first thought was maybe the block has a hairline crack near the starter mount, from trying to start it last year with water in the cylinder. But it was starting initially
He says there are no worn teeth on flywheel?
Someone suggested his bolts may be bent?

Any thoughts or help is appreciated, Thanks.

You're going in the right direction... however cracking the starter bosses on the block would take something freak. It's always worth a look. My question lies more in whether or not the flywheel is true, and perhaps if it's even tight. Who put the bellhousing/flywheel on?

Since he's reporting three diff starters I doubt this will help, but, I had the same issue after a starter change...worked fine for 4 or 5 starts then ground. Initially my thought was flywheel but, I found both starter bolts loose. Tightened them down appropriately and no promblem since.

Are you sure there is no water getting in now?

I checked out the flywheel some teeth are a little chewed, maybe 16th or 32nd, but it doesnt seem like enough to cause this problem.

We spun the motor over by hand/crank bolt to check out all the teeth, the plugs were out and no water came out of plug holes. We found a good clean spot on the flywheel and I put the starter in. we tried to start it, it grinded and sheered the front bolt off clean, in the block. This is crazy. it was an old bolt but still...

now we go back and try the inline bolt high torque starter.

Any advice...

my,
You have been through too many starters, I dont think another one is going to fix the problem. Unless it is a very high compression engine, it should not need anything more than a stock starter. I think you have another problem. Is the ignition timing correct ? It almost sounds like it might be kicking back. Also, it does not take much wear on the ring gear teeth to keep the starter from working properly.

The only other thing is to check all of the starter wiring and especially the grounds going to the engine block. Take them loose and clean the connections with a wire brush. It does not take much corrosion on a starter cable to keep the starter from making its full power.

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

Also check your starter bolts. I found some to be 1/4" longer then the factory and the starter would snug up but not tighten. Then it would twist after a few tries. Did you reuse exisitng bolts?

Nordic95

You can get new starter bolts at the chevy dealer. Check them and make sure they aren't bent and definitely torque them down correctly.

Kind of gee whiz but also make sure the plug wires are on the correct cylinders? We all make mistakes...

In your first post you said "So he got a new marine mini starter" If this is a mercruiser starter, it comes with its own l bolts and you must use them.

I read wear you changed out the head gasket, I had this same problem a few years ago on a 454 mag. Hydro locked the motor, broke starter bolt off 'in block' and knocked teeth off of ring gear. It turned out that UNDER the riser / manifold gasket was rusted out and let water into one cylinder. I would pull risers and check under gaskets....