Stihl FS 55 weed eater issues

rjh1

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#1
stihl fs 55 weed eater issues running . . . what I've done thus far - replaced muffler ,it was very carboned up , compression is 120 lbs no leak down . . replaced carb and fuel line .. new spark plug .. now won't idle .. will run on choke for a couple seconds .. won't run off choke .. have tried to adjust new carb 1 1/2 out on both screws ... no good :mad: this thing has me totally baffled ... need some major help Please !
 

billr

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#2
There is probably a strainer/screen at the end of the fuel line inside the tank, also probably weighted so you can operated in all attitudes. Have you checked that it is still on the line, and is it clean? This is a two-stroke, right? There are probably reed-valves or similar between the carb and crankcase, those can go bad and compression won't be affected at all. Two-stroke carbs are notoriously finicky, but this one is new, so I won't make my usual suggestion of just taking it apart and blowing out all the passages and jets...
 

rjh1

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#3
yes fuel filter is on the line , it is a nylon type . i put new fuel line in also so i know filter is attached . i do have a new felt type filter i could put on and try . The prob i had with the other carb was it would idle but when u trigger it up it bogged and you could see a gas mist coming out the carb ? , even after the new muffler .. that's why i put on a new carb .. I can't seem to find a parts breakdown for this unit ? if this thing has reed valve or valves where are they ? can you supply a picture or a link to a parts breakdown site ? Thank You !
 

billr

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#4
This is a 2-stroke, right? Blowing back through the carb is another hint that it is a reed-valve problem. Those are often on a thin plate sandwiched between the carb and the crankcase, but I don't have any pictorials to show it.
 

rjh1

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#5
Had to take low mixture screw out to 2 1/2 turns and Hi screw to 1 1/2 then adjust from there , all is good so far ( fingers crossed ) ! Thanks !
 
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#6
This riding mower is from the laye 1980s. I havent been abe to do any troubleshooting on it yet. Im hoping there is something disengaging the main drivebelt like a defective seat kill switch or possibly a switch on the deck that disengages the blades when the deck is fully raised.
 

billr

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#7
This sounds like it is a legitimate plea for help, but for machinery completely different than in the original (and old) thread. Please start a new thread, giving the make, model, year, and problem symptoms of what you have.