I agree with some of the posters above. Your engine doesnt sound fried first off. Second, get on youtube and watch some tuning videos! This will be where you may see what your doing wrong. I am lucky that my lhs has people that know what they are talking about but I would not call most of them experts in all aspects of the hobby. Some of them know electric well, some of them nitro, some airplanes and heli's. The track is your best bet to get someone who really knows what they are doing. If there is not a track near you youtube and searching this forum is where you will do most of your learning.
By the way, my engine wouldn't tune and was hard to get started. I found out that it had nothing to do with my carb settings, piston, sleave, conrod, bearings or anything else in the motor. It was a bad clutch spring that was causing the clutch to engage to early and stalling my motor. I could never get it to idle right untill I change springs.