Hi,
I have a Magnum 91xls that I am trying to break in but I ruined the sleeve and piston. I used a fuel containing 18% of oil which I added castor oil to bring it to 25%. Then I ran the engine on a test bench at full throttle but not too rich or not too lean. I ran the engine 5 runs of 1 minute each and I let the engine cool down completely between each run. Then I ran the engine 5 minutes three more times letting the engine once again cool off between each runs. Every run, I tried to lean the engine slightly more. I then mounted my engine in the airplane but during the flight, the engine leaned out and overheated and upon landing, the piston and the sleeve were cooked!!! The engine still works but I lost some power... Also, I measured the engine temperature while it was on the bench with a laser temp gun, temp was around 350 to 380 degree Far, On couple instances, the engine overheated at what point I made it more rich or stopped it. So I ordered a new piston and sleeve and I was wondering if somebody has an easier and safer way for the engine to be broken in. I don't want to kill the new sleeve and piston.... I need to protect the engine from the user (me)
Thanks,
Le fou