yes- vaccum leaks are deadly, they are what cause my first blasters motor to blow, the whole motor too not just the top end. We figured out that right before i bought it the chain flew of at high speed and put a whole in the case, causing a small oil leak, but even worse causing a vaccum leak, which blew the motor and 700$ later.. well you get the point. Deff. check the carb first like he said, just cleaning it could probably help. I also had alot of float problems with mine and it always leaked out of the overfill. So do that, do a sparkplug, and if not.. well then it's prolly a lil more surious [img]i/expressions/face-icon-small-confused.gif[/img]