RE: After Run Oil And Omega Fuel ( Morgan )
Properly taken care of and run dry at the end of a flying session, any engine using a fuel with a considerable castor content will have less of a need for after run oils than an engine running total synthetic lubes or one with wet fuel left in the engine.
Are you going to hurt anything by adding your favorite after run oil (assuming it's appropriate for that type engine)? NO, you will not, just don't hydro lock the engine the next time you go to start it up.
Several fuel companies, including mine, use lubricants that have some anti-corrosion properties in the synthetic. Castor has always been the best corrosion inhibitor for model fuels.
Hope this helps shed some light on the subject.
Fuelman
Cooper Fuels