Just bought a 89 Ranger first Boat, it has a 89 Mariner 135 hp on it, The book said mix 50 t0 1 the guy i bought it from said he was mixing it 100 to 1 plus i noticed he had oil in the resvoir, for injection it runs great at idle it has like smoke around engine cover but when running no smoke. im thinking to rich with oil at idle speed any ideas?