stihl 034 carb

[brian034]

Just finished a top end rebuild on my 034 and due to parts availability I had to go with the 48mm piston kit instead of the 46mm piston the saw came with. The saw starts, idles and runs fine. If I apply a quick full throttle I can hear a fuel starve condition. On a slower acceleration I don't seem to hear it as much. When it reaches full throttle it seems to run fine. Does anyone know if the 48mm saw used a different jet in the carb? I haven't done anything with the carb yet as I'm trying to figure out if I'll need to replace it with one of the several models listed for that saw or rebuild what I have and possibly go to a larger jet. All carb internals although old looked ok and the saw seals, fuel filter and lines are good.

 

[d.l.d]

Just did the same build about three weeks ago and the old Tillotson 034 carb. worked just fine. I did rebuild it before i put it on. Seems if everything else you say checked out, then as long as the carb. is in good shape a cleaning and rebuild kit should do the trick. I always do a vacuum/pressure test onthe saw when putting a new piston/cylinder kit in just for insurance if i dont know how it died

 

[the GOAT]

Have you adjusted the carb at all?

 

[farmer]

sounds like a carb diaphragm needs to be replaced, then carb adjusting. the 024 and 028 do the same thing

 

[brian034]

Zama Carb has been adjusted and set with a tach. Idles fine doesn't stall and seals tested fine before rebuild. I was worried there may have been a different size jet and finding out I should have replaced the carb instead of rebuilding it. They list several different carbs for that saw and there are different metering end covers.

 

[d.l.d]

I've used the zama carb that came on 034 for the 036 conversion and it worked fine also. If there has been ethanol in it and it sat in it for any lengthy time at all the diaphragms will be harder and not preform correct. As for the metering covers I've only seen two different types on the zamas. The 034 thats flat and 036 that has a square on the filter side for the compensator style carb. They also take different air filters for each. As far as re jetting the carb, I've never had to do that for any "big bore" conversion for it to run right. Ony adjust the carb.

 

[Nitehawk55]

Should be fine but the diaphrams would be suspect as well as the needle setting if the rest of the fuel system is fine .

 

[cgraham1]

I've gone from 64cc to 84cc on a Dolmar/Makita with very little change in the carb settings. I don't think a 5cc jump could make that much difference in carb settings.

 

[trooney]

I agree with Clint . I dont think a change of a couple of cc's would require a carb to be set that much different.

 

[cgraham1]

Maybe just a carb rebuild. Did you check out/replace the fuel and impulse lines while you had it apart?

 

[drf256]

The ZAMA replacement carb for that saw costs around $20 to your door. You just need to sway your metering cover onto it.

 

[DexterDay]

Is the original flock filter on it? I built a basically brand new MS 360 from the ground up (except the air filter). The flock filter looked clean, but it was jam packed with fines. A new filter and that saw was a beast.

Filter can reak havoc on a tune..

 

[brian034]

Rebuild kit for the carb is sitting on the kitchen table and hope to have it completed this weekend. I'm guessing it was a problem that was starting and going to larger cylinder kit just pronounced it enough so I could hear it.

 

[brian034]

Put the carb kit in fired it up and could tell the first time I hit the throttle the problem was solved. Seems to run fine now thanks for all the input.

 

[DexterDay]

Glad she is running good for you again!