I could use some help with this one...I have a McCulloch trimmer that is giving me fits. New piston and cylinder, compression is around 125 PSI, crankcase holds pressure and vacuum. Spark seems to be O.K. I have been through the carburetor several times and it always passes the pressure test. I have checked and adjusted the metering lever to make sure it is just flush with the floor of the carburetor.
Unit will start easily, often without choking it at all. Runs fine for a minute or two then starts bogging down, threated to die if I open the throttle, and then dies and won't restart. You can hear what sounds like fuel boiling in the cylinder after it dies. Frequently when it is just setting there hot or cold it drips fuel out of the carburetor. How can that be if the metering needle is seating properly as evidenced by the pressure test? Has anyone had a bad experience with the check valves in the primer/purge bulb section of the carburetor?
Mark