I need to replace it and cant find in parts manual, mine is bad. I looked at a couple from 98 gtx limited I have laying around and they don't have a washer. Is the washer necessary? Thank you all!
I have never seen a rotax oil pump without a washer. But I have not worked on your model of machine so I can't 100% back up my words. If it was mine I would look for a brass washer at the hardware store.
I think they should have the copper or brass washer to help them seal but you could clean it up really good and put some Loctite Gasket Eliminator on the surface to seal it but that is only good for a one time. Auto parts store may have them (think brake parts) as well as Amazon. I recently had the kind of leak you had and sure enough my bleed bolt did not have the washer.
It is a Mikuni oil pump. Mikuni may offer some. Any other machine that uses a Mikuni pump may have them Also can look at McMaster Carr website. Can most likely get aluminu,copper of fiber washer there that will fit.