I picked up a used 019t yesterday. They told me it dies out. Got her home started cutting wood ran good but then i saw the problem. At full throttle it dies out kind of like it was bogging form being to rich. Then it would load up and just die out. Then i would have to restart and blip the throttle to get it running again. The saw dose idle good. They told me its been to the dealer a few times and keeps doing this. Any ideas what i could be?