Why not flexplate?

[curtis73]

I have an older Alpha sterndrive that uses the coupler that shares the flywheel mounting bolts. So why all the extra weight with the flywheel? Aside from the slightly thicker profile of the flywheel, what is preventing me from using a flexplate instead? Shaves a ton of weight, both for rotating mass and a little for displacement.

[Frosty]

A flywheel does have wieght and thats to help the engine to run smoothly especially at low speed tick over.

The reason that a flexplate can be used in an auto tranny is because the torque converter itself has the mass required.