I can suggest a
route. Find the exploded parts manual for both engines and see if the parts match. My bet is that they do. These are Kubota engines, so you might go there.
Westerbeke bought Universal, and charges horrendous prices for their remaining stock of parts. A Westerbeke/Universal starter for my Universal M25 is $1,164.95, while the same starter from a tractor supply that sells Kubota parts is $68.80. The throttle cut-off turns out to be a stock item at heavy
diesel equipment supply houses, and the
fuel pump is also a stock item. The
alternator pretty well has to fit both.