Help with early Stihl 034 problems

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CountryBoy19

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BLUF: I need to replace or rebuild carb (I think), it's an early carb and I may be better off replacing.

Saw: 034 marked West Germany, TIllotson (Made in USA) HK-43A carb. According to what I found on another forum this means it was one of the first 3 years production for the 034 saw.

Dilemna: This carb has a seperate plastic metering plate that the needle seats into. Supposedly this plate can cause issues over time. Rebuild kits aren't impossible to find, but it took me a while to find that Tillotson RK-33HK is the PN for the kit. Would I be better off to just replace the whole carb with the Zama carbs that came on later 034 models?

Backstory: I inherited this saw from my dad, he bought it in the 80's from an older gentleman that had grown tired of dealing with it's cold-blooded nature. I believe that gentleman was the original owner and rarely used it; my dad rarely used it as well. Anytime the saw has sat for a day or more, it's very temperamental getting started. Dad got tired of it and bought a new Dolmar and gave the 034 to me as a spare. It has sat on the shelf for 3+ years; I didn't plan to run it because it's somewhat sentimental to me.

Fast-forward to a terrible day last week when I discovered a crack in the mag case (not directly in the crankcase thankfully) on my Dolmar and had to dig out the 034 to cut up a big downed tree. The only way I could get it to start and run was to pour gas through the air-filter, it would run for a bit on choke (it was getting some fuel through the carb when choked) but I would eventually "lose it" and it was slowly ramp down and sputter out. A little splash of gas on the filter and it would fire right up if choked. Take the choke off even slightly and it would die. So it's starving for fuel. Needless to say, I cut that tree up with my MS170 and rolled it out of the way for a day when one of my big saws is running.

Things I've checked: intake boot, fuel line, & impulse line all seem good. The impulse line is a little stiffer than the others but they are all still flexible with no cracking or brittleness. Slightly pressurizing them didn't revealed any leaks or pinholes. Fuel filter in the tank is good and flows fuel well. I tore the carb apart and there is no obvious tearing/wear/etc on the diaphragm, reed-valves etc. Gaskets all seemed good. There was some dirt/oil in the vent on the diaphram and the other vent. I see no reason why the carb wouldn't work with a rebuild kit but knowing the back-story maybe there is a deeper issue going on?
 
The Zama replacement carb for them now is the C3A-S19 , these carbs have the compensator cover on them but they can just be plugged or the cover can be replaced from an older Zama. Media Cat does not give a listing or part number for an older version Zama that would work, there a couple other Zama versions, same as the one I posted above, all of the carbs now have the compensator covers with the snorkel, all of them can be plugged to keep debris out.
 
The Zama replacement carb for them now is the C3A-S19 , these carbs have the compensator cover on them but they can just be plugged or the cover can be replaced from an older Zama. Media Cat does not give a listing or part number for an older version Zama that would work, there a couple other Zama versions, same as the one I posted above, all of the carbs now have the compensator covers with the snorkel, all of them can be plugged to keep debris out.
That compensator cover was my hang-up, it looked like it would be too big and could possibly cause interference but if I can just plug it and go on with life that's the course I'll take...
 
That compensator cover was my hang-up, it looked like it would be too big and could possibly cause interference but if I can just plug it and go on with life that's the course I'll take...


Get a carb from an 036 non-pro WO compensator. I think Pioneerguy600 gave you the part # ? My 036 IPL shows both covers and I'm not sure if it's shipped with both?

You might be able to a good used, try trading post.
 
That compensator cover was my hang-up, it looked like it would be too big and could possibly cause interference but if I can just plug it and go on with life that's the course I'll take...
They will fit and can be plugged, at least they are new and not something that will need rebuilding. I find used carbs that are being sold are often problematic carbs someone else has tried to fix and they still won`t work, they then just try to get rid of them to unsuspecting buyers. I personally am done with buying used carbs, just a crasp shoot for my experience. The compensator cover can be switched if not wanted and there is always a chance one could find a NOS older Zama, that would be great.
The older Zama carb without the comp cover would have been a C3A-S4
 
You can also cut the compensator horn off at an angle. Tape over hole and fill with JB weld. When it’s hardened, drill a small hole for air to reach the metering diaphragm.

I do it all the time. The metering horn won’t allow the airfilter to seal if left alone. You can’t plug it with anything after you cut it off, the angle is too abrupt. You will apply pressure to the metering diaphragm and flood the saw out.

The replacement Zama carbs are apparently made on the same line as true Zama’s In fact, up till about a year ago, they came with Zama cast into the pump plate. They still come with “C3A” cast into the side.
 
I like the modification using JB weld if you can't find a non-compensator carb. I can see this working for 026 saws too

My older 036 IPL shows a few carbs and some show both covers

Carburetor C3A-S31E (1,2) Carburetor CA-S65 (6) Carburetor C3A-S27D (3) Carburetor C3A-S39B (4) Carburetor C3-S52 (5)

(1) 036, (2) 036 W, (3) 036 WVH, (4) 036 PRO, (5) 036 Arctic, (6) 036 BR

The non-compensator end cover is : 1125 121 0803 was available 2017 $7.50 USD
 
The Zama replacement carb for them now is the C3A-S19 , these carbs have the compensator cover on them but they can just be plugged or the cover can be replaced from an older Zama. Media Cat does not give a listing or part number for an older version Zama that would work, there a couple other Zama versions, same as the one I posted above, all of the carbs now have the compensator covers with the snorkel, all of them can be plugged to keep debris out.
Seems most of the cheapos on ebay are C3A-S31A or C3A-S39B... are those different or will they substitute just as easily?

https://www.ebay.com/itm/New-Carbur...270873&hash=item465eab4647:g:jHUAAOSwXYtYsjZ0
https://www.ebay.com/itm/Carburetor...695295?hash=item3f536e937f:g:YpQAAOSwo4pYYtIU
 
Ive had about 50 50 results reviving carbs with rebuild.
As stated above ive also bought some carbs on ebay i couldnt get to work properly.
New is best but sometimes a tear down of carb clean and backtogether works
 
I picked up a used HK-43A Tillotson for my 036 and couldn't get it to work. I rebuilt it and did everything short of a ultrasonic cleaning. I might pull the welch plugs and try that. I could get it tuned well but starting the saw was an absolute bear; basically had to de-tune it and pour gas in the throat to get it started. Couldn't see where there could be wear on the metering plate because there is a metal insert for the needle valve on the plastic plate itself. Put the original non-compensator Zama back on it and it works fine.
 
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