# Help with some part numbers.... FS55 brush trimmer



## andrethegiant70 (Apr 15, 2018)

Hi, all! Wow, been quite a while (again.)

I purchased a busted FS55 brush trimmer from my Stihl dealer a while back. About 7 months ago I moved back to Cali and brought it to fix up and use on my new property. It's a nice-looking unit that didn't appear to have many hours on it. Absolutely MINT piston, clean spark arrestor, but would not fire up. I figure it just sat for a while and the fuel system needed a refresh. I checked all the usual suspects... had an extra carb, so i popped it on, changed out the rubber, and installed a new fuel filter and spark plug, just because I had one.... it has good spark, compression, but you can pull on that sucker all day long, and it doesn't even come close to starting, even with a shot of mix into the carb. What it WILL do every once in a great while is backfire out of the carburetor or go fffffttt out of the exhaust. It seems to me that the timing is jazzed up. So I broke it all the way down to check flywheel key, which seems to be in the right spot. Hmmm... starting to see why someone gave up on this thing. I read all the posts here, which seem to indicate that it's possible that the ignition can fry in such a way that there is a good spark, but the advance circuit is shorted. I bought a Chinese coil, popped it on, adjusted it, and reassembled. Exactly the same symptoms! To my dismay, I also read that, at some point, they switched coil and flywheel timing.... bummer. Here's what I think happened.....

When the unit came in for the repair, the dealer replaced either the flywheel or the coil and managed to mismatch them. Not knowing this, I may have replaced the coil with the wrong match for that flywheel. Alternately, my Chinese coil may be the right one, but it's a cheeseball part.

Rather than just throw parts at this thing, I'm wondering if some kind soul has an IPL for this bugger? Or if someone has the respective part number matches for the flywheel and the coil, that would work also. I did manage to find a partial IPL online and it showed a single part number for the flywheel and three part numbers for the ignition. Uh oh. I REALLY hope the Stihl IPL isn't that way, or I'm dead in the water.

All that being said, I'm wide open to suggestions. Thanks, in advance....

Andre


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## ray benson (Apr 15, 2018)

andrethegiant70 said:


> Hi, all! Wow, been quite a while (again.)
> 
> I purchased a busted FS55 brush trimmer from my Stihl dealer a while back. About 7 months ago I moved back to Cali and brought it to fix up and use on my new property. It's a nice-looking unit that didn't appear to have many hours on it. Absolutely MINT piston, clean spark arrestor, but would not fire up. I figure it just sat for a while and the fuel system needed a refresh. I checked all the usual suspects... had an extra carb, so i popped it on, changed out the rubber, and installed a new fuel filter and spark plug, just because I had one.... it has good spark, compression, but you can pull on that sucker all day long, and it doesn't even come close to starting, even with a shot of mix into the carb. What it WILL do every once in a great while is backfire out of the carburetor or go fffffttt out of the exhaust. It seems to me that the timing is jazzed up. So I broke it all the way down to check flywheel key, which seems to be in the right spot. Hmmm... starting to see why someone gave up on this thing. I read all the posts here, which seem to indicate that it's possible that the ignition can fry in such a way that there is a good spark, but the advance circuit is shorted. I bought a Chinese coil, popped it on, adjusted it, and reassembled. Exactly the same symptoms! To my dismay, I also read that, at some point, they switched coil and flywheel timing.... bummer. Here's what I think happened.....
> 
> ...


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