HI FOR break in i add 1oz of castor oil to my OMEGA fuel in the first tank only ( not in the gallon saves fuel )run the engine just below max rpms -on a 1 inch smaller prop than you will use to fly the engine (jet engines has very good break in info on his web site ) run the engine for a minute or two then let it cool downi like to keep the piston at the top of its travel so the liner and piston cool together (contract together just me ) what is happening hear is the metals are being polished and hardened at the same time from the heating and cooling temps ( the cooling is as important as the running now )do not for any reason overheat the engine at this timetouch the head with caustion (tap it ) to feel it -s/b very warm but not sizzling hot everi run a 16 oz tank for break inor until the engine will hold its nv settings (varies with engine mfg's )
i only use after run oil ( a mixture of 1/2 trans fluid and mystery oil ) when i am putting an engine to rest for a whilei use to use it every day i flew only to find the engine needed to clear it out before it would start to perform as it should for a days flying (worked against me the next day to get the engine performing well when flying a few days in a row) so now i only use it for storage-not required for daily use if using MORGAN OMEGA FUEL per the instructions again my .02 cents ENJOY REGARDS TONY