You have to use after-run oil to prevent corrosion, besides that, there is nothing better than use after-run and remove the engine then store y in a ziplock bag. I have only used good fuel, Power Master, Cool Power and some Cosmo (very difficult to get), and the fuel is definitely the only variable which is responsible for the engine condition under proper storage, and even though they say they have anti oxidants etc, good maintenance practices are above any else.

The engine is very reliable provided, good fuel is used, good plug and valve maintenance and very good tune in, the later determines if an engine will be a great engine good for 400 flights without dis-assembly or a nightmare after 100 or 150 flights.

Regards