Ok I'm new to RC's so I'm still trying to learn how to tune my RC and get it running to its full potential...

Ok I have two RC10GT i bought used, both using OS max engines........... I was able to get both up and running to where I thought was fine, then my friend told me I'm running to lean and started making adjustments to my RC's........

Well long story short with one of them it starts up and rev's at full throttle for a few seconds and spits out alot of gas through the exhaust then dies, I was able to get it to stop that, and now when it starts up it just dies........

The other one won't start at all.........

My question is how to I set both needles back to their original settings, I know the low needle is clockwise til it stops , but what about the high needle?????

How can I check to see if my engine is damaged etc etc if its more then just a tuning issue??????

Thank You