RE: Evo Engine Plug Problem - HELP !
I know you said the plane is a trainer but you didn't say if it has a cowl or is closed in. If the engine is closed in be sure you have enough air flow going in and 3 times the opening for air exit. You might also want to try a couple different props just to see what happens. I use FOX Miracle plugs with NO problems.
A few years ago I had a well known flier show me how he tuned his engines and it's worked great for me. : Get it started and let it run for a few seconds then take it to about 1/2 throttle and tune it to it's highest RPM then richen the needle about 1/8 of a turn. Now try full power, it should take it and run smooth - leave it alone !!!! ENJOY !!! RED