Agreed! Time to get this back on track and get you moving.
Install the correct propeller that has been balanced. Use 15 to 20% nitro pattern fuel with at least 20% oil content. Using less oil will cause damage to the engine. Look for fuel marked 20/20 pattern fuel or the like. AVOID fuels that are labled 2 and/or 4 stroke as all that I have seen don't have enough oil. Prime the engine and get it started to run. You will need a tachometer to set the engine. It is all but impossible to set a 4 stroke without one properly. Bring the engine up to max RPM and then back off 300 rpm while breaking the engine in. Don't do any long strenuous maneuvers like very long uplines, downlines at full throttle or loops with no throttle down on the last half. The trick is to use the engine through all throttle settings. Getting the engine lean will cause it to backfire and spit the propeller off. The engine will naturally lean out near the end of the tank so be aware and lower the throttle setting. The idle won't be best until a good bit of fuel is run through it. Ringed engines take longer to run in. Use fresh fuel and a good plug (OS~F four stroke is what many use). Have your igniter fully charged or use a power panel with a meter. Good luck,

EXCAP232