Chainsaw Repair

First of all you have to center the wheel on top dead center .The easiest way is to use some type of piston stop .Put it where you think TDC is then rotate it one direction and write down the degrees then rotate it opposite to the stop  and again write them down . If for instance you're 10 degrees one way and 5 the other then set the wheel for 7.5 and check again .When it's equal on both rotations you've found TDC .

Mac Dizzy covers it pretty well if you want to look .