On Fri, 03 Jul 2015 21:11:30 -0400, J Burns wrote:

On 7/3/15 6:57 PM, wrote:
I have a 2-cycle trimmer that was working just fine. Then during it's
last use the speed began declining while in full throttle mode until
it finally died. I changed the spark plug and now it only runs with
the choke closed. If I try to open the choke or let off the throttle
the engine dies. Any suggestions?


Mine is nearly 35 years old, but I guess they are the same in many ways.

I have a Walbro carb. On the side with the fuel inlet is a plate held
by a center screw. That's the pump compartment. With the choke on and
the throttle open, the pump gets bigger air pulses to pump harder. For
me, the problem has usually been that moisture in the fuel has caused
the outlet screen of the pump to clog. A q-tip and a little cleaning
solvent will fix it.

The last time, gas deposits on the face of the body against which the
pump gasket seated, showed that I had an air leak, which kept the pump
from working right. Removing the deposits fixed it.

I'd go with what J B said. (After all, he invented welding.)