This chainsaw was not running so I rebuilt the carb and it started after a little help, but now has no acceleration I have adjusted the carb(Zama) numerous times and at different settings it only gets worse, feels like it was binding but took the chain off and does the same thing. Another thing I noticed was that the sparkplug tip was grayish /white before I rebuilt the carb. I have checked the compresion and it is around 120 psi could there be a possibilty that this engine got hot at one time?