Hi Brian, I replaced my A4 with a Yanmar 2GM 14 years ago and have enjoyed dependable operation since. First measured height, width, depth, length from shaft center line and shaft coupling to be sure it would fit in the available space. Built a frame to locate engine mounts, shaft half-coupling, length and width of the 2GM and control locations with dimensions from Yanmar drawings. Strung a wire from the cutlass bearing thru the stuffing box to a secure fitting in the cabin to represent the shaft center line and positioned the frame on this wire to determine engine bed dimensions, exhaust configuration, control cable layout, etc.
I was lucky. The engine bed height was increased by 1.5 inches, the shaft coupled to the engine with out changing shaft location or length, and a waterlift muffler and 2 inch exhaust hoses were a comfortable fit. I installed the engine control panel on a piece of plexiglas in the same location as the old panel and the old choke button is now the engine shutoff. A Racor fuel filter was added to the fuel line This has worked well for 14 years although the water injection elbow in the exhaust was replaced last spring. I wish you well on your project. Chuck Barr Meerschaum [Non-text portions of this message have been removed]
