I just read an extensive article where Pennzoil tested 4 503's with 4 different oils, 2 of which were Pennzoil air cooled and Pennzoil multipurpose. The results show that the multipurpose is OK for use in the Rotax 2- stroke. I am having trouble getting the air cooled Pennzoil and I am thinking of switching. Will sooner or later have to switch to something else. Any thoughts on what I can do?-------rick
http://www.ultralightnews.com/features/oiltest.htm