Steve,

I have been using Marvel Mystery Oil for years. It is available from Wal-Mart or any good auto supply store. It is red and has a distinctive smell. It has been around for years and is good stuff. Another good oil is any good AIR TOOL oil which you may have to do a little searching for this item. Any shop that deals with air tools should have it. Hope this helps.

I use the above oil exclusively for my after-run oil to protect ball bearings. If your engine does not have ball bearings, it is still good to protect the crankshaft from rusting. I always run my engine dry of any fuel residue, then I usually fill the carb up twice, I hand crank both loads into the engine after which I spin it for a second or two with my electric starter to distribute the oil.

Paul