So today at the field I was trying to crank up my OD 46 sized engine.
http://www3.towerhobbies.com/cgi-bin...XFMD5&P=ML

Immediately the engine started sputtering and it became stiff and the prop would not turn easily.

My instructor took a look at the engine and we found this :





He told me that my engine has run a bit lean and my piston was scratched.

I'm asking for any advanced pilot to help me fix this problem.

My instructor's suggestion was to buy a new piston:

http://www3.towerhobbies.com/cgi-bin...LXGCU6&P=Z

I am not willing to spend 76$ on this new part.

Is there like some solution I can use to fix it?

Or is there anything I can do?

If you want to buy it go ahead, because I am clueless of what to do...