# Stihl FS 80 AV Carb. problem



## martym

I've just rebuilt my carb. and the trimmer will only run when the choke is on or I have my finger over the carb throat. It will eventually die. What pumps the fuel from the tank? When I pump the bulb fuel transfers from the tank thru the carb and out so I assume the line and filter is ok. I wonder about the flappers and gasket stack up? I also wonder about the needle valve and the small brass pin that I could pressup and down but was unable to remove when rebuilding. I do have experience in repairs but carbs. are my weakness. I'm new to this forum, read all of the comments under 2 cycle engine repairs refering to my trimmer. Can I bypass the primer bulb? Any help would be appreciated. Martym


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## 30yearTech

The carburetor on your engine is probably a TK slide valve carbuetor, and has a fuel pump that draws the fuel from the tank into the carburetor metering chamber, there should be adjustment screws on this carburetor to increase/decrease the fuel through the main jet. There should be (3) screws a large one with knurled edges that is the idle stop screw, a medium brass colored screw that should be the main jet adjustment, and a small air bleed that is used to compensate for wear in the slide valve needle. Open up the medium size screw 1/2 turn out and try it again and see if there is any difference in the way it runs.

Good Luck


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