propcut,
An OS 46LA would work fine on a 24x24 PBF, but a ball bearing 40 to 46 sized engine is really too heavy.

The PBF is really designed to perform best with the bushing 40 or the ball bearing 25 to 36 sized engines. And even with these engines, full power is only needed for hard maneuvering.

If you have to use a ball bearing 46, then you might want to consider enlarging the PBF to at least 30x30, or maybe even 36x36.