This has recently happened to my '82 Hobbit were it will only idle with the choke on, and then quickly high rev and die with the choke off unless your giving it a bunch of gas. Is there a fix? I've taken it into a shop cleaned the carb twice, just put in a new crank so I highly doubt there is a leak in the crank case, cleaned the air box, got a new filter, a new spark plug. If anyone has any idea's it would be greatly appreciated!!