What cause my gas trimmer to rev up on choke, and stall and die when it is contained by the "run" position?
Answers: Probably needs a good cleaning, to unstick dirty sticky parts.
The bright poulan trimmers are made by homelite, and are the best non-commercial trimmer made in the last ten years.
Since it wont decline, you need to adjust the idle fuel mixture screw, it have plastic caps on it for "emissions" reasons, consequently only allowing you to adjust minutely.
Turn counter clockwise as far as it will let you, the start it. Adjust clockwise until it idle fine.
As for the revving up only on Choke, the throttle fuel mixture screw must also be out of adjustment. The same applies for the setting of this one.
Some things you can do to improve recital, take the muffler apart and remove the spark arrestor screen, this eyeshade will plug up with carbon, and will keep the trimmer from revving up properly within the future.
Come to think of this one, if you hold run it for a while, this may be your problem!
Next, once you have adjusted the fuel screw, and know which is the throttle screw, pull the plastic head stale with a pair of linesman pliers, you will the know how to adjust the carb to its fullest potential.
You do have a good trimmer, BUT, it is singular made for occasional use, up to 50 hours. It will likely only be righteous for a season or two of commercial use.
Next time, spend $250 and buy a 30cc Stihl or Echo. It will outlast those residential trimmers by ten years.