My engine wont stay running while it is cold. If it hasnt ran for about ten minutes it will sputter and want to die if its given any throttle, almost like the choke is on. I jetted up the main one size when a pipe was added. I also run with no airbox lid now so should I jet the main up again? Should a different change be made to the carb, like the pilot jet? The main jet is the only one Im familiar with so any info will help.