1. Have you used treated fuel for use and storage if you use ethanol fuel?
2. Have you serviced it yearly (plug/filters) and given it good general overall look?
3. Have you checked the fuel lines and primer bulb for no cracks/air tight fits?
4.Have you checked the basics needed to run fire/fuel/compression/exhaust (muffler spark arrest?
5. If you do not know basics, do you have a friend, neighbor that knows the quick checks?
6.Most needed info related to your symptoms have been discussed with solutions, if you Google info/questions.
7. Approx how many hours of use per season? Please share you find or results.

Good Luck!

Hi Simon,

I have the Stihl FS 55T Kombi unit. (It is called Kombi because you can change out the lower unit with various tools: a string trimmer, an edger or other various tools.) I purchased it June 14, 2003 so I've had it for 11 years. It has given me trouble twice and both times it was similar to your situation: it either wouldn't start or wouldn't stay running.

The first time was in July 2011. I had a new carburetor installed, $81 out the door. Ran good for the next three years.

Same problem started again in February this year (2014). I recognized the symptoms this time, as it was so similar to the last time. I am a big DIY-er (do-it-yourself) kind of person, and I watched a ton of videos and read a lot of forums but in the end, realized it was probably the carburetor - and a job too big for me - and I took it to the shop. They installed a new carb and once again, $76 out the door. (The price of the carbs has actually gone down by $5.) This time, I had a long talk with the technician and he told me that I have to start using ethanol-free fuel. The carburetors in these just don't last with regular fuel mix. Here in Jacksonville, you can buy ethanol-free fuel at Gate Gas Stations and also most boat marinas. So that is what I am now doing.

I hope this is helpful. Let us know what you do.

Carol in Jacksonville

1. Have you used treated fuel for use and storage if you use ethanol fuel?
YES
2. Have you serviced it yearly (plug/filters) and given it good general overall look?
NO - Checked plugs a couple and air filter a couple times over the years but not annually
3. Have you checked the fuel lines and primer bulb for no cracks/air tight fits?
HAVE NOT DONE ANY CHECKS OTHER THAN NOTING THEY SEEM INTACT
4.Have you checked the basics needed to run fire/fuel/compression/exhaust (muffler spark arrest?
NOT REALLY BUT SEE BELOW
5. If you do not know basics, do you have a friend, neighbor that knows the quick checks?
NO
6.Most needed info related to your symptoms have been discussed with solutions, if you Google info/questions.
7. Approx how many hours of use per season?
UNDER 10 - I run this around 3-4 times a month on average to trim grass on 2 sides of the house, around deck, and a couple other small spots the mower can't get to. Probably 10 to 15 min each time.

I was going to just replace but watched a few videos and got a bit more ambitious. I removed spark arestor, did a more thoughrough job of cleaning spark plug and tried starting without air filter and using a little wd-40 as starting fluid (saw that on another web site). It now starts up and runs rough and slow. I tried adjusting carb but couldn't get it to run better than a fast idle. Any attempt to use it the motor dies - but at least the fact that it will start is promising (I think). From most of what I've read it sounds like the issue is the carb. I think I'm going to try taking it apart and cleaning it as I've seen on some youtube videos. Worst that will happen is I won't be able to re-assemble it in which case I'll either buy a new trimmer or decide to buy a new carb. Called local dealer and he wasn't too anxious to see a new carb - they said they'd have to order it and cost would be $50 tp $80. But I see these on Ebay from USA sources that can deliver in less than a week for under $30 (cheaper direct from the orient).

Any thoughts would be appreciated.

I did all the things you describe - watched tons of YouTube videos - I removed and cleaned the spark arrestor - soaked it for days in mineral spirits - all that - but in the end, the carburetor still needed to be replaced.

From what I understand, treating ethanol-based fuel with fuel stabilizer doesn't mitigate the effect of ethanol. It doesn't help. However, there are other products specifically for treating ethanol fuels - and they do help. So there are different products when people say they are using "treated fuel". Not sure which treatment you are using.

Surprising that your service tech isn't interested in installing a new carb. If you have the skills to do it yourself, my money would be on the $30 from eBay and put 'er in. I bet you'll be back in biz. From everything I read - and you probably did, too, since you've done the same research - the common solution is replacing the carb.

I've switched to the ethanol-free fuel and hoping to get more than three years this time. When I bought the Stihl, it was supposed to be the be-all-end-all.

Carol

Here is a link that might be useful: STA-BIL products

The fuel oil mix I've been buying (either Stihl or Echo) has indicated it has a stabilizer in it so I haven't been adding a separate stabilizer. I do use Sta-Bil in my mower and snowblower 4 cycle equipment.

With my recent internet searches on all this I've read some things about the pre-mix fuels for 2 cycle engines that purport to be better, ethanol free alternatives. The brand most seem to carry is Trufuel. This runs around $5/quart which is pretty pricy but I don't go through much more than a gallon a year, if that, so it wouldn't be too bad if it helps a lot. I think I'll switch to that in my trimmer and blower after I use up my existing gallon or figure out how to properly get rid of it.

The dealer I called would have no problem servicing my trimmer but they didn't seem too interested in selling me an uninstalled carb. All three of the places I tried calling around here have the same deal: Roughly $30 inspection fee with no estimate, even a rough one or average, until after they've done the inspection. From what I've been able to find on the internet repairs seem to run from $75 to over $100. I live in Chicago suburbs which tends to be on the expensive side for repairing anything and don't want to invest $30 to find out I'd have to spend another $75, total of around $100, to repair a $150 trimmer. Plus everyone is running about 2 weeks before they can begin to look at it this time of year.

For a bit I was just considering buying a cheapie trimmer - $70 at Home Depot or Lowes but those seem to have pretty poor reviews even under light use. If I can't repair mine I'll probably by an Echo at home depot for $200 which gets good reviews and has a 5 year warranty even though it is a bit of overkill for my needs.

All depends if I can get mine going before the areas around the house which need trimming get totally out of hand.

Please post back about how easy/difficult it was for you to install the new carburetor. I would love to know how it goes.

Here's a link to a great page of info on ethanol-blended gasoline. Loaded with good info.

Carol

Here is a link that might be useful: The 411 on Ethanol

Well.... while it hasn't hit the trash yet it looks like "pitch it" is the winner.

I was considering getting a cheapie trimmer ($70 or $80 range) rather then spending money on a carb that I wasn't sure I could install or would fix all problems and rather than spending around that amount, more or less, on having someone repair it for me. But the reviews on the low end gas trimmers had a substantial number of complaints on all sights so I took a pass on that idea.

But in looking over the reviews I happened on reviews from several sites of the Black and Decker battery powered trimmer model LST400. Reviews were pretty good and this model has a 2x battery for either more power or longer run time. So I decided to give it a try.

I've used this a couple times and I'm happy with it for now. Just hope I will still be happy in a year or two or five. It definitely doesn't have the power of the gas trimmer but I seldom, if ever, really needed that power. I use the trimmer mostly for trimming grass along the side of my house and around areas the mower can't reach like posts and deck steps. The Stihl wasn't very good at edging as it was too hard to control but the Black and Decker actually did a very nice job maintaining a neat edge on the lawn. I edge the lawn periodically with a metal bladed corded electric edger but seldom trimmed the edges in between as the Stihl was too hard to edge with. But the B&D unit works great as it is light weight and has a special head adjustment and a wheel for edging.

The battery powered tools have apparently come a long way in recent years. If someone had to trim through lots of brush and/or needed a long run time then the battery trimmer might not be good for them. But for my needs on my residential house lot it seems like a good choice. After two trimming sessions it has plenty of runtime, and just enough power, for me.

I bought one of the $80 cheapie trimmers last year - a Murray. It starts, runs, and trims really well, but that sucker sure is Loud! I think they've had to open up the muffler on some of the cheaper brands to meet emission standards. You probably made a good move with the battery powered B&D.

Boy, I have more rechargeable batteries in things around my place that *don't* hold a charge... I sure wouldn't do that. Nothing that I own that is battery-powered holds a charge for as long as advertised. By the time the battery life starts getting to be a real pain, the ability to return the product is also a pain.

I would spend the $80 or so to put a new carburetor in the Stihl and then use the proper fuel to keep it running well and have a decent trimmer. That would be me. It sounds like you haven't put any money into the Stihl in six years, other than the original purchase, right?

True that I haven't put money into it the Stihl in the past but haven't had any problems up to now either - although it's never run as good as I thought it would. Even when new it was hard to start and a bit finicky at restarting when warm.

But in any event I've already bought the battery operated trimmer. So for better or worse we'll see how it goes.

I don't know where you live or the size of the lot you are trimming. In the mid 90's I bought a corded string trimmer, and used it until a couple of years ago, at that time It was Dead. During the about 15 years that I had it, I did all of the trimming necessary around the house and trees.

Yes the cord was a problem BUT with planning those problems could be minimized. No mixing oil, no recharging batteries, just plug it in and use it.

When we moved to our current house and the corded trimmer finally died, I bought a Cub Cadet 4 cycle gas trimmer. The new gas trimmer goes to all corners of our 3/4 acre lot and does a good job on the stones in a ditch on the property line.

The only thing I have to do is check the oil, fill it with gas, and it starts per the manual. I never do any winter preparation, nor use any stabilizer in the gas. Even after sitting in the shed through the winter months it starts easily the first time in the spring. The bad thing is it is noisier that my corded trimmer, but I don't have to put up with the cord, which to go the 300 feet in our new lot would be a pain.