go to one of the larger outlets & get rubbing alcohol in the largest container they sell. our fuel is alcohol based & it will cut the oil very nicely& cheaply.be careful of exhaust deflectors. a SHORT one is fine but excessively long one ( ive seen them wrap tied all the way to the main gear!) are asking for trouble sooner or later. too much back pressure & over heating or premature wear. our engines are designed to use the muffler expansion as supplied .excessive back pressure only ads to the heat.