[McGillicuddy]

Sorry that prop ain't workin' right.
Seems another Seacraft owner had a running angle issue and one of the points made was relative to the amount of negative trim on the Yammie engine mounts. Apparently a mount design adapted to overcompensate for the weight of their four strokes.

Could such a trim angle be working in conjunction with that prop to be causing your bow stuffing?

It might be helpful to post some side shots of the motor all the way down.

Do you have trim tabs?

Love to see pics of your old prop, too.

Why not pitch down in similar geometry. Old school yammi props are still being made.