Since you have the marine version, the flywheel housing and drive plate conform to an SAE specification and should not be Nissan specific. If you look at this: http://www.marathonelectric.com/generat ... saedim.pdf
it looks like you have an SAE 7-1/2 housing. That broadens your search options since now all you need is an SAE 7-1/2 drive plate for a BW drive. This standard is common on industrial and marine applications so that any engine will bolt to any drive or pump or generator or whatever.
Thank You PB, Its a good day when I learn something,like pieces of a puzzle, Maybe I can get the price of this plate down to earth, as soon as you say"marine" it becomes a $395 friggin specialty! Forklifts,Generators,Pumps... Back to the hunt!,
THNX, JD