These guys are distributors out of Hansen, Ma. They have always had anything I have ever needed for my Westerbeke genset.
Be prepared to open your wallet, but the parts are all genuine Westerbeke.
There may be a distributor near you, check online.
Thanks Scott this guy is the man for Westerbekes. I gave him the model an SN and he told me what it was doing. After talking to him it seems he has a large number of parts for older gens