Stihl FS55 Problem


Old 05-28-08, 01:10 PM
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Join Date: May 2008
Posts: 1
Cool Stihl FS55 Problem

So i have a FS55. Its a great machine like all stihl are, but im having a problem. When i push the primer bulb pressure builds up in the tank and the fuel doesnt make it back to the bulb. I pulled the carb apart as much as i could without messing with the gaskets and blew out every hole i could find with my speedair. after i put it back together the same thing is happening. so i took it in to the shop and the guy shook it without fuel in it and said the fuel line in the tank wasnt connected because he heard something shaking around inside and that was the problem. this sounded kind of stupid to me but i tried it out, and after taking the tank off and pulling the fuel line out and seeing the filter and line in tat, i put it back together and added gas and the same thing happened. i also tried blowing out the holes again. where is the clog? should i try to get all new gaskets and diaphram and try that? i dont know what else would be going wrong

thank you for any help you can give me!!

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Old 05-28-08, 06:39 PM
Join Date: Jun 2006
Location: St. Louis
Posts: 2,365
Sounds to me like a bad fuel line, sucking air rather than fuel and pumping/returning air to the tank. Replace the fuel lines and fuel filter. Have a good one. Geo
Old 05-28-08, 09:58 PM
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Join Date: Jul 2001
Location: USA
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If the tank is pressurizing, then I'd say the carb needs to be cleaned. You'll probably find the needle is stuck and/or the inlet screen is clogged among other possibilities.
Old 05-29-08, 08:42 AM
Join Date: Nov 2007
Posts: 128
Remove the carb, then over a clean box remove the 4 screws
on the primer bulb side, then remove the one screw on the
other side, under which you will see a screen, the passage under the screen goes to the lever/needle on the other side.
Remove this, and be careful not to lose the spring.
Then with all of this removed, blow out all of the tiny little holes, and visually verify that the passage under the screen is clear, then reassemble, that should improve your problems.


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