G'Day and welcome Daf Boy.
Something that will help us is an approximate locstion as this Forum is world wide. Usual places to look other than here will be the auction sites and talking to some of the boat builders local to you who may have a lead to an engine. The more places you visit and ask the better the chances are that you will find one.
Sometimes things turn up quickly and other times you need to be patient. Wish you luck looking for the engine and that you find a good one. Let us know how you get on.