Loaned out my 02 gtxrfi the guy I loaned it to put gas in the oil tank, dont know how much he got in it because oil was recently full. What kind of problem will this cause and should I drain and fill with fresh oil?
Use a syphon pump and syphon the oil and gas out then refill with seadoo genuine 2 stroke oil. You may be able to use the old oil for a premix in an old lawn mower or something.