View Full Version : Stihl FS55 Trimmer help

10-18-2008, 10:07 AM
I have a 4 year old FS55 trimmer. Early this summer, it started running rough, when I give it some gas, the engine dies.

I finally took it into the dealer and they are telling me it needs a new carb. Can this be true?

Richard Martin
10-18-2008, 10:22 AM
That's my thought. There is really very little that can go wrong with these simple 2 stroke engines. If the coil, plug, filters and compression are good then more than likely it needs a carb. Is it hard to start? How is the primer bulb? A lot of people might say it has a gas cap vent problem but that doesn't account for it running rough.

10-18-2008, 10:39 AM
Once it starts, it's pretty decent, just if I give it full throttle, the engine dies. A friend said to check the muffler screen. Any idea?

Also, I use 89 octane, should I be using something higher, like premium gas?

10-18-2008, 11:39 AM
I had a similar problem with my fs85 this season. I changed all the filters, new fuel line, new plug and sprayed cleaner in the carb. It still ran a little rough, but was getting better, so, I cleaned the carb 2 more times. That seemed to do the trick. Good luck with it. Also, does it need a new carb, or does that one just need a rebuild kit?
Dave in Dayton

10-19-2008, 11:45 PM
Can I get something I can mix with my gas to clean the carb?

10-20-2008, 12:15 AM
I use the spray cleaner. And definately check the muffler screen and the air and fuel filters. If you want, you can PM me and we can exchange numbers or e-mail if you want more help.