Starter mount keeps breaking.

[colemaxwell]

I work at a marina, and one of the boats that I was assigned to had a broken starter mount. After taking off the necessary hardware, I was able to remove the old mount and replace it with a new one. A few days later the boat was back in the shop with the same problem. I replaced the mount once again, started the motor and engaged the throttle in forward, everything seemed fine. About the 3rd time I started it up, there was a loud cracking sound, and I noticed that the flywheel is what is breaking the mount because it is making contact with it, and it broke once more. Any suggestions as to why this keeps happening? Everything is tightened down and (seemingly) functioning properly.

Yamaha 250 Fourstroke

 

[jimn]

I work at a marina, and one of the boats that I was assigned to had a broken starter mount. After taking off the necessary hardware, I was able to remove the old mount and replace it with a new one. A few days later the boat was back in the shop with the same problem. I replaced the mount once again, started the motor and engaged the throttle in forward, everything seemed fine. About the 3rd time I started it up, there was a loud cracking sound, and I noticed that the flywheel is what is breaking the mount because it is making contact with it, and it broke once more. Any suggestions as to why this keeps happening? Everything is tightened down and (seemingly) functioning properly.

Yamaha 250 Fourstroke

The throttle shouldn't have anything to do with the starter. Are you working on this boat in the shop, or on the water? If possible, do it in the shop so you can watch the gear when it engages, to see if the Bendix is hitting the bottom of the flywheel's teeth.

You wrote "noticed that the flywheel is what is breaking the mount because it is making contact with it"- the flywheel is hitting the mount? How is that possible? What other parts have been changed and is this boat in your shop because another shop couldn't fix it?