# Stihl TS 500i will only accelerate with help from primer bulb



## Waterone (Sep 20, 2020)

Just bought this saw at auction, and put fresh fuel in it and it will start, but, when I try to rev it up it will not unless I press the primer bulb slightly while holder the trigger. Once it's reved up it runs strong, however, when trigger is released and it returns to an idol it will not rev up again unless the primer bulb is pressed. Has anyone else had this issue?


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## stihl86 (Sep 21, 2020)

No I haven’t But I’d start by taking the muffler off. Then, if you can a vac/pressure test. There is a fuel pump incorporated into the primer that needs crankcase pulses to work


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## Waterone (Sep 21, 2020)

stihl86 said:


> No I haven’t But I’d start by taking the muffler off. Then, if you can a vac/pressure test. There is a fuel pump incorporated into the primer that needs crankcase pulses to work


Thanks for the reply! I will try that this weekend.


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