# Replacement Carb for old Stihl FS 80 (TK carb)



## quid_non

Hi all!
Got an old Stihl FS80 with a TK carb (slide barrel) that will start but not run for more than 5-10 sec - it constantly floods out. I found a rebuild carb kit and installed - no difference. Compression is good (~150psi), great spark - I just hate to trash this thing.

I followed several strings about these TK carbs being known to wear and leak air into the carb. I have not "eliminated" the primer bulb or plugged up the overflow port -do you think this will help?

Lastly - I've searched the net for a replacement carb, but can't find one.
How would one go about matching a different (newer) carb to this - what things do I need to consider? Has anyone doe something like this?

Thanks for any help.
Best
quid_non


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## geogrubb

quid_non said:


> Hi all!
> Got an old Stihl FS80 with a TK carb (slide barrel) that will start but not run for more than 5-10 sec - it constantly floods out. I found a rebuild carb kit and installed - no difference. Compression is good (~150psi), great spark - I just hate to trash this thing.
> 
> I followed several strings about these TK carbs being known to wear and leak air into the carb. I have not "eliminated" the primer bulb or plugged up the overflow port -do you think this will help?
> 
> Lastly - I've searched the net for a replacement carb, but can't find one.
> How would one go about matching a different (newer) carb to this - what things do I need to consider? Has anyone doe something like this?
> 
> Thanks for any help.
> Best
> quid_non


Manual shows for FS80,85 the following, Zama C1Q-S63A, C1Q-S78 BR, C1Q-S56, C1Q-S60 BR, C1Q-28D, C1Q-S41A and Walbro WT-447
Have a good one. Geo


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## quid_non

Thanks - but this has the slide barrel carb (TK style) - will the ones you mention interchange with this? It is the OLD FS80.
Thanks


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## geogrubb

quid_non said:


> Thanks - but this has the slide barrel carb (TK style) - will the ones you mention interchange with this? It is the OLD FS80.
> Thanks


I do not know, maybe one of the other guys has the answer and will post after they get off work. Have a good one. Geo


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## geogrubb

quid_non said:


> Thanks - but this has the slide barrel carb (TK style) - will the ones you mention interchange with this? It is the OLD FS80.
> Thanks


I do not know, the manual I used didn't show a TK carb so maybe it doesn't go back far enough, maybe one of the other guys has the answer and will post after they get off work. Have a good one. Geo


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## pioneer 1074

A possible source for a replacement carb might be www.chainsawr.com


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## quid_non

Thanks for the link Pioneer - an interesting site. Did not find any carbs here for trimmers.
Thanks!


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## Lawnmowertech

quid_non said:


> Thanks for the link Pioneer - an interesting site. Did not find any carbs here for trimmers.
> Thanks!


You can try my site but i am sure if that is a stihl unit stihl and the carb manufactures made it impossible for non stihl dealers to get carbs for the stihl units so it may have to be special ordered from your stihl dealer


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## quid_non

Thanks Lawnmower tech!
Still can't seem to find any info. Wondering if scouting local repair shops for discarded carbs is an option.

What does it take to put a different carb on an engine? What should I consider - Why can't I just put a walbro on instead of "TK" (I need to fabricate an adapter) but why not?

Thanks for any insight


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## luckyvision

I'm a Stihl dealer, & i'll check for you tomorrow. Stihl has a propriatary parts look up called Media Cat. FS80 isn't very old, so carbs should still be available. normaly for any product there will be several carbs listed in the look-up, the newest 'version' will be listed at the top. any chance you can post the serial number of the unit? Thanks, --Lucky


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## luckyvision

as a start: 

4112's:
(1) FS 80 E,(2) FS 80 AVE,(3) FS 80 RE,(4) FS 80 AVRE
carb is Stihl part # 4112 120 0611

there are 8 different carbs for units #4137


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## quid_non

Thanks for the follow up Luckyvision - soorry it took so long to get back with yuo.
Serial # 
Stihl FS80AVR 13654169

btw...
Tried the "modification" suggested by others (i.e. drilling out the "tickler valve" and plugging the overfolw port). (see: http://www.arboristsite.com/showthread.php?p=977903) This had no effect - the carb still floods out. Replaced /rechecked the float pin, spring and lever - - still floods the cylinder.

At a loss on what to try next - can't seem to locate a replacement carb...


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## geogrubb

quid_non said:


> Thanks for the follow up Luckyvision - soorry it took so long to get back with yuo.
> Serial #
> Stihl FS80AVR 13654169
> 
> btw...
> Tried the "modification" suggested by others (i.e. drilling out the "tickler valve" and plugging the overfolw port). (see: http://www.arboristsite.com/showthread.php?p=977903) This had no effect - the carb still floods out. Replaced /rechecked the float pin, spring and lever - - still floods the cylinder.
> 
> At a loss on what to try next - can't seem to locate a replacement carb...


Here is a Zama. Have a good one. Geo
http://cgi.ebay.com/Zama-Stihl-FS-8...140?pt=LH_DefaultDomain_0&hash=item3a5e1ad9b4
Here is a TK carb kit.
http://cgi.ebay.com/TK-Carb-Kit-Ful...075?pt=LH_DefaultDomain_0&hash=item2c56e5aad3


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## quid_non

Thanks - still looking are a replacement carb or substitute. I installed a kit and it makes no difference. The zama is not a slide barrel type. Wondering if it will match up with the hole pattern on the case?

Any other suggestions??
Thanks


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## geogrubb

quid_non said:


> Thanks - still looking are a replacement carb or substitute. I installed a kit and it makes no difference. The zama is not a slide barrel type. Wondering if it will match up with the hole pattern on the case?
> 
> Any other suggestions??
> Thanks


Refer to my first post, all of those carbs listed are for an FS80 the info came from the Stihl manual. Have a good one. Geo


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## quid_non

Thanks for the reminder - but none of these will fit this early model FS80!
How can I retrofit to accept one of these?


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## geogrubb

quid_non said:


> Thanks for the reminder - but none of these will fit this early model FS80!
> How can I retrofit to accept one of these?


I would suggest asking a Stihl dealer. Have a good one. Geo


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## 30yearTech

Early Stihl FS-80 trimmers were actually units vended to them and not manufactured by Stihl. I think they were manufactured by Mitsubishi. The Shindaiwa T-25 trimmer used pretty much the same TK carburetor found on the Stihl and I have used them on the older FS-80's. Alas they are no longer available, so unless you can find a Shindaiwa dealer with one in stock you may be out of luck.


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## Turd Fugeson

quid_non

Did you ever have any luck finding a replacement carb? I'm in the same boat as you. Looking at the carb mount it looks like any trimmer carb might be able to be used but a new spacer/adapter plate would have to be made. I'm just not sure what carb would be a good candidate for a conversion. I did run across a rc car that had the old fs80 engine with a newer walbro on it.


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## wbley

*Old FS80 primer bulb*

I am resuscitating an old FS80 Stihl trimmer ( bought in 1978!!!) with the black rubber primer bulb on the gas can. The bulb is rock hard and needs replacing ...the problem is the bulb is no longer sold . Has anyone got one or know of a work around solution to this problem? The bulb is actually smaller than the smallest ZAMA bulb I could find. Is there a generic "Primer bulb" kit that could be inserted into the system? Any other solutions you have would be welcome! Thanks wolf


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## wbley

*Possible solution*

Shindaiwa 20000-85303 part # may be the solution. It appears to be an in line primer pump that should fit this Stihl as well and it is still avaliable. wolf


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## trailr8d

*modified FS80 works great*

:wave:Hello folks, first time poster.

I have recently successfully swapped out the crappy TK carb for a more modern design. I believe from a newer FS85 ( will post carb # later). with a little machine work on the plastic carb spacer, a bracket to use the existing throttle cable and removing the old tank mounted primer, i have aprox 10 hours on it since i started the conversion and with minor tweakin it seems to be performing just fine. will post pics and instructions when i'm totally satisfied with the performance.


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## quid_non

Hi Trailr8D!
Great news - can you send more details - I'd really like to try this!
Thanks


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## mudduck001

quid_non said:


> Hi all!
> Got an old Stihl FS80 with a TK carb (slide barrel) that will start but not run for more than 5-10 sec - it constantly floods out. I found a rebuild carb kit and installed - no difference. Compression is good (~150psi), great spark - I just hate to trash this thing.
> 
> I followed several strings about these TK carbs being known to wear and leak air into the carb. I have not "eliminated" the primer bulb or plugged up the overflow port -do you think this will help?
> 
> Lastly - I've searched the net for a replacement carb, but can't find one.
> How would one go about matching a different (newer) carb to this - what things do I need to consider? Has anyone doe something like this?
> 
> Thanks for any help.
> Best
> quid_non


go to amazon FS85 will fit also. type: replacement carb FS 80 it will tell you what that carb will fit.


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## paulr44

In the future, please start a new thread.

_Sounds_ like the inlet needle isn't seating properly. Using a mity-vac or other pressure tester, connect to the fuel inlet on the carb. and pump it up to 8-10 psi. If it can't hold that, that's the problem. Polishing the seat with a cut-off baby Q-tip in a drill with fine grit valve lapping compound may help. Of course a new inlet needle valve as well if you can find one. *Most parts for that unit were obsolete like 10 years ago. *While it was a workhorse, parts availability puts you in a bind. This pressure test is what us _pros_ use to check for a leaky inlet needle.

Never heard of air leaking into a carb. creating a flooding condition, sounds like someone off their meds. I'm STIHL Silver, RedMax and EETC 2-stroke qualified with 40+ years rebuilding carbs. from Quadrajets and Carters on cars, Zenith/Bendix on 4-stroke and Bing to Zama on 2-stroke. A 4-stroke carb. with a clogged vent will overflow, a 2-stroke diaphragm carb. has no vent - it's moot.

However, I have seen excessive sawdust on top of the metering diaphragm atmosphere side causing it to depress and thus flood. But very, very rare. Also collapsed diaphragms can make it flood, but usually just make it run too rich. But leaking air? Tell me something new...

And, albeit rare but worth mentioning, I have seen Winter grade fuel which has a higher vapor pressure cause flooding when carried over and used in very warm OAT conditions. Easy way to check for this, loosen the gas cap and try it then, or change out the mix if suspect. But again, very, very rare.









Mityvac Silverline Elite Hand Pump MITMV8510 - The Home Depot


The Mityvac Silverline Hand Pump gauges the vacuum and pressure during leakages, fluid transfer and fluid drainage. It conducts engine performance diagnostics. It features an optimized design with Aluminum



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P.S. Walbro service manuals provide excellent visual illustrations of how diaphragm carbs. work, free to download.


https://www.walbro.com/service-manuals/


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