any suggesting for breaking in Irvine 1.20. have started this engine using the following: Master airscrew classic 16-08 prop wildcat fuel 10% nitro synthetic castor blend 80-20. very low compression at first-ringed engine characteristic i quess. tachmetered at idle 2000-reved to 10000. Have run only for brief periods (it does seem to want to stop on its own also-is it getting too hot??) Someone suggested 5%-total castor fuel.
Any info appreciated.

Add 4 to 6 oz of extra Castor to your break-in fuel, 5% nitro. (10% should be OK). Run a ringed engine sloppy rich during break-in, let it run a few minutes at a time. Let it cool between break-in runs.

Hey Howard, nice to hear from you at the universe. I would be glad to help you set it up.
My bigger ringed engines never have much compression until they have been broke in, If you have it very rich you may want to leave the glow igniter on it for the first tank or two, and it should be VERY rich for the first few tanks.
I never go above 5000 rpm for the first tank.
The low speed needle may need a little tweaking, How is the transition, stuttery or smooth