Stihl Trimmer FS80

chargerandyJuly 28, 2007

I have had an FS80 given to me by a frustrated, non-mechanically inclined prior owner. This unit needed a carb kit and a little TLC. I bought the carb kit and need any input on a starting point for all the tuning screws on the carb. The prior owner had monkeyed with it enough that everything is wayyy out. Any help please?

Thanks,

Andy

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fisher40037

First, we need to know if it is an old FS80 of the newer style, what brand carb/kit did you buy?

Fish

    Bookmark   July 29, 2007 at 2:46PM
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chargerandy

Alrighty then, let the fun begin..... Did not know there was two different generations of these little trimmers. I looked up the carb kit online (Zama kit rb-66) and ordered that. Well, it's either completely wrong for my machine or it's for a newer generation. Mine I know is around 8 to 10 years old.
Sooooo, now I not only need the carb screw settings, but also the proper kit. I will look for any numbers when it comes apart. I knew this would be more fun than my old Cummins Dodge. ;-) Anybody got a diesel line trimmer?
Thanks for your post Fish, I will get back on here when that carb's apart.
Andy

    Bookmark   July 29, 2007 at 7:33PM
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chargerandy

OK, carb's not apart yet, no time this weekend. The number on the intake flange is 1D10N. On the outside of the throttle bore there is a symbol in the casting that is somewhat of a circle with an "IK" within the bottom edge of it. I assume this to be the manufacturer's logo. The carb has a flat bowl at the bottom with a green tickler button. The back of the carb (facing away from the trimmer's head) has a round fuel lift pump ass'y. The gasket set I have does not provide for any of this, so I know I goofed. Can anyone turn me onto the correct kit and screw settings? Anybody need the aforementioned carb kit that I have now?

Thanks,
Andy

    Bookmark   July 29, 2007 at 9:02PM
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fisher40037

You have the "OLD" FS80, with the TK carb. Your trimmer
is at least 20 years old.
Go back to your Stihl dealer, and tell him he goofed, and you need the old fs80 carb kit, and a copy of his "mediacat" carb instructions. He should comply.

Fish

    Bookmark   July 30, 2007 at 7:12PM
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fisher40037

BTW I am an old Stihl tech, so I did not expect anyone else to know.

    Bookmark   July 30, 2007 at 7:23PM
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dino_1

I also had one of these units given to me. It is definately the old carb style, it has the high speed, low speed and idle screws in a row right next to each other and does not look like the carb in the current stihl fs80 manual. I have the unit running but cannot seem to get it dialed in correctly. It runs fine but when you give her the throttle most of the time it will severely bog down, almost to the point of stall. I have adjusted to my hearts content but cannot seem to get the right combo. Somtimes it behaves as it should but it seems to be before it is completely warmed up. Please advise of any suggestions.

    Bookmark   September 20, 2007 at 5:51PM
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johnsess

You can get a rebuild kit for the TK carb for your old FS-80 at bantasaw.com out of Canada for $17.00.

John

    Bookmark   December 27, 2007 at 1:09PM
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fisher40037

I can sell it for a lot less than that.......

Fish

    Bookmark   December 29, 2007 at 8:00PM
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iangregg

I have one of these with the same symptoms as dino_1. I have not adjusted it ever but now it dies with throttle unless I give it lots of choke. I am off to get a carb kit and soak the carb bits in acetone or similar to try and clean off any old scum but I would appreciate any hints especially in regard to setting the screws when I put it back together.

    Bookmark   February 1, 2008 at 5:37PM
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iangregg

Put the carb kit in and got it going and thought I was a hero. BUT!! After 30 mins running fine it stopped, I thought from lack of fuel. Put more fuel in and it has not run since! Stripped the carb and cleaned it again. Changed the fuel. Now what do I do?

Ian

    Bookmark   February 4, 2008 at 12:23AM
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rmh3481

Hi Ian,
On your stihl fs80 trimmer you first need to check for spark and compression. To check for compression w/o a gauge; remove the spark plug and then hold your thumb over the sparkplug hole while turning the engine over with the pull start. You should not be able keep all the pressure in the cylinder with your fingertip no matter how hard you try. Next, check for spark by putting the plug back on the wire but do not thread it in to the cylinder. Touch and hold the threaded end of the plug to the cylinder and then pull the engine over with your other hand and look for a spark at the tip. You may also be able to hear the spark if its good and hot.

I hope you had some oil mixed with your gas when you had that trimmer running? If not its going to be needing a set of rings.

I would also replace the fuel line going from the filter to the carb, and wash out or replace the filter. The carb jet which is closest to the cylinder is the low side, with the other as the high side. Rotate each in to the cylinder with a screwdriver while turning clockwise untill the jets seat. Next turn each jet out 1 and 1/2 turns to start. This will get the engine running. Allow the unit to warm up for a minute and adjust the low side jet clockwise by 1/8 turns for the highest idle speed. Once you have attained the high idle, back the jet out an additional 1/8 for good acceleration. Next is the high side, go to full throttle and adjust for highest speed. Again back the jet out an 1/8 turn counter clockwise from highest rpm to keep the high side from being too lean under a load.

Hope this helps you sort it out. Make sure you use a quality air cooled engine oil for your fuel mix. If you have any questions please post them.
Best wishes,
Bob

    Bookmark   February 10, 2008 at 6:32PM
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iangregg

Bob
Thanks for the good info. It has compression, spark, it is definitely the carby. I have disassembled and cleaned everything several times. It has run occassionally for 10-15 secs. I now have it running but with fuel dripping continuously from the vent line. The valve that is supposed to seal the vent does not seem to be serviceable. I phoned the local dealer and was surprised to be told that I could order a new carb for this old snipper but was then disappointed to find that it would cost AUD 200 +. I am off to buy a whole new snipper if I cannot get the vent to stop leaking fuel.

    Bookmark   February 11, 2008 at 12:37AM
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kckeith

I haave a fs80 stihl with a tk carb and the adjustment screws are all in a verticle alignment. which one is shich amd how do I adjust them??

    Bookmark   April 20, 2008 at 12:14PM
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jim_hijkl

TO: Fish
I too have an early-style FS80 with the TK slide-type carb and am looking for a complete overhaul kit. Mine began running up to 12K WOT and the hi jet adjustment seems to not work to bring down the WOT RPMs. I think the slide may be worn; allowing excessive air to leak past at the intake. You mention above that you have a kit for these TK's. What all is in the kit? Thanks/Jim

    Bookmark   May 28, 2008 at 3:55PM
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fisher40037

The aftermarket kits are just gaskets and diaphrams only.

Most of the other parts are nla from Stihl, but some older dealers may have them in stock.
One other possibility is to find a Shindaiwa dealer, and
check on parts for their old t25 trimmers, they had
pretty much the same carb.

Fish

    Bookmark   May 29, 2008 at 12:01PM
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jim_hijkl

Thanks Fish - I'll try the Shindaiwa dealer tomorrow.

    Bookmark   May 29, 2008 at 9:35PM
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gorper99(4a)

LandscaperPro has a clearance sale on complete carbs for $9.95 each.

    Bookmark   June 1, 2008 at 2:59PM
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nate81

i have an old stihl fs80 and lately (2 or 3 weeks now) It will start up w/ a few pulls, and run ok for half of the yard. After a while it will die out when i give it throttle....if i ease into the power real slow it will sometimes catch and can run full throttle...but most of the time it just kills it with even a touch of the throttle. I've noticed some white smoke coming out of it at times also....sometimes quite a bit when it first starts up. There is a stihl shop down the road, how much should it cost me to get this problem fixed? thanks for helping i realize this is a really old thread

    Bookmark   May 7, 2010 at 11:57AM
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Bobp24

I have a Stihl FS 80 trimmer, and the carb has only 2 screws for adjustment, 1 for the idle, and 1 other, most post's talk of 2 or 3, an idea's on how to adjust this carb? Thanks

    Bookmark   August 7, 2014 at 12:39PM
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the_0utsider

Bobp, I may be wrong but i recall it is 2 turns.

From my experience with my fs80, after rebuild kit, i could never get it to work not even pump fuel to the carb so i gave up with the original. I ended up modding a current fs80 carb with 2 mix screws and drill a hole in the tank was my fix.

fwiw

    Bookmark   August 11, 2014 at 10:46PM
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