I have limited knowledge of the Jonsered chainsaws but all the larger Jonsereds that I have been around pull over really hard and some come with decomp and others don`t. If a chainsaw engine gets out of timimg, like advanced in this case it can cause them to be more than difficult to start them. Some fellows I know advance the timing on their saws by a few degrees by removing the key in the flywheel and crank. They place a dab mark on the crank and one on the flywheel as witness marks once they decide where the optium timing is for their saw and then just torque the nut down on the flywheel. It makes them hard to start for the uninitiated but once you learn how to drop start them they aren`t so bad. Check for the key to see if its there, it can also be a module going bad that makes them break down at higher revs or the timing thing again.
Pioneerguy600
