Need some opinions...

[Rob]

I know this is a Donzi board, and this is not a question about my Donzi, but there are so many great mechanical minds out there, I'm going to ask anyway.

My 87 Mastercraft stopped transmiting power to the prop a few days ago (i.e. engine turns, output shaft on transmission does not). Thinking that perhaps the transmission (Borg-Warner) had given up, I pulled it out. Come to find out, it's not the transmission after all, but the flex plate. The thing is trashed.

Now this boat is 13 years old, but I'm really easy on it. And my maintenance routine is way overboard. I'm puzzled why this seemingly simple and foolproof component would suddenly and completely collapse.

Any ideas? Is there something I'm missing in the operation or maintenance of this boat?

Thanks-rob

[Hotboat]

Is it possible that you hit something in the water? The spring loaded flex plate could have been the part that absorbed the lick and busted. Check your prop and shaft. Do you have a three finger plate or a full circle? With a lot of horsepower & torque you need the full circle.

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Hotboat

[AVickers]

Check the runout on the input shaft, check that all the crank bolt are tight and check the flywheel runout. Also, check the alignment of the housings -- bell-to-engine and transmission-to-bell -- to be sure they line up w/ the centerline of the crank.

Could be that something was bent slightly or not fully lined up. If nothing has come loose (to cause an immediate alignment problem), then my thought is that if it took 13 years to break 'cause of any of these problems over time, I'd probably just get a new drive plate and put it back together -- to be reconditioned during year 10.