"Grant" wrote in message
...
Stern drive boats do indeed have a flexible coupling between the engine
flywheel and the intermediate shaft which attaches to the universal
joints.
In the BMW it is a flexplate with a spline. The Mercruisers have a rubber
coupling.

Cam


And, I have seen them with slots instead of holes due to wear. Thing is, if
you can hear it in the boat, that is usually where the problem is, though
can be upper gear case
as well.

Dan