I took a mid 80s crusader 454 down to a long block and dressed it with mercruiser accessories. Left the crusader flywheel on the engine and low and behold i have a starter that now just spins and doesnt engage the flywheel. How do i figure out if this engine has an internally balanced or externally balanced flywheel? I have the mercruiser flywheel i can swap over, but don't want to do that if the engine is externally balanced.

I believe you have the wrong starter of that flywheel, 168 tooth starter, you may need a 153

the ring gear can be an innee or an outee depends on where the starter is located

another thought is if that engine had a rear top mount starter the ring gear was moved to the back

EDIT: if its ext balanced it will have a counter weight on it

The engine had a top, bell housing mounted starter, and now has a block mounted starter.

Remove it heat the ring and move it to the front

Like F2 said you need to move the ring gear. Knock it off with a brass punch and a big hammer. Put the ring gear in the oven at 450 degrees for a half hour and it should fall right back onto the flywheel on the correct side.

Thanks guys, now only if I knew this before I got the engine hooked all back up and drive back on...

Raray888 has to be an AI bot no one talks like that in the marine mechanical world

Ya I reported raray but nothing has been done to remove it