Could it be the gasket that goes between the inspection plate and the bellhousing came loose and got balled up behind the flywheel? The inspection plate is the sheet metal part that bolts to the bottom of the bellhousing around the starter and such.

Other than that, I am baffled.

BT

jafo,
If there is something between the block and flywheel, is it around the crankshaft? Or is it laying behind the block by the soft plugs? Or is it between the coupler/plate and flywheel? I know of nothing that should be there in either spot. Maybe it fell in there during manufacture? Maybe a rare option that makes your boat worth millions.. Just kidding. I cant think of what it could be.. Can we have some pics please. I am sure we are all dying to figure this one out!!

Good luck..

Dick

I believe the engine coupler is mounted in rubber..
i will post a pic of mine , as it is out on the floor in my shop..
it sounds to me like you need a new coupler....

Here's the pic

Ok?? I see the coupler, but wheres the seal you were talking about. Unless your talking about what your pointing at. If so than thats just the Coupler Not a seal