Stihl 034 won't idle
- Thread starter elscorch
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redunshee
Addicted to ArboristSite
How did you know what level to set the metering lever? Did you just lower it a bit? Reason I ask is you stated you didn't know which model of Tillotson you had. Also with compression test I assume you pulled recoil until compression needle stopped rising.
Yes on the compression test, for the metering lever I found a tillotson manual for a similar carb and just deduced from there. Lever was to the top of the small depression in the metering chamber.
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knoxman
ArboristSite Lurker
I have the same problem with "erratic idle and dies" on my 034
What is correct metering lever adjustment for the zama carb? using a feeler guage I measured ~20thou lower than gasket surface
Background: I've had this saw for 9 years, and it's always idled poorly; runs good at WOT; 145psi compression; did crank seals; passed pressure and vac tests; put a new carb kit in it some years ago; fully cleaned carb last month; verified carb needle valve holds 7psi from tank pickup line; replaced impulse line; verified fuel tank is not building suction (tho I did recently remove the vent rubber flapper because it would build pressure when I brought it indoors in winter) - not impressed with that old vent design).
As my next steps, I'm planning to verify metering lever adjustment and then install another carb kit.
What is correct metering lever adjustment for the zama carb? using a feeler guage I measured ~20thou lower than gasket surface
Background: I've had this saw for 9 years, and it's always idled poorly; runs good at WOT; 145psi compression; did crank seals; passed pressure and vac tests; put a new carb kit in it some years ago; fully cleaned carb last month; verified carb needle valve holds 7psi from tank pickup line; replaced impulse line; verified fuel tank is not building suction (tho I did recently remove the vent rubber flapper because it would build pressure when I brought it indoors in winter) - not impressed with that old vent design).
As my next steps, I'm planning to verify metering lever adjustment and then install another carb kit.
knoxman
ArboristSite Lurker
Quick Follow-up in case it helps others: I made up a gasket between the carb and intake boot; it was missing when I got the saw; now it runs/idles well till 1/4 tank at which point the filter isn't fully submerged - I guess it needs a new more flexible fuel line.
I'll tentatively conclude my metering lever doesn't need adjusting.
I'll tentatively conclude my metering lever doesn't need adjusting.
The Stihl 0 series saws do not have gaskets between the carb and boot so it was not missing on your saw, the most often overlooked piece is the round metal ring that inserts inside the opening of the boot directly behind the carb, it keeps the rubber from deforming and not making an airtight seal. Does your boot have that ring in it? , if not then that is why it is not sealing to the carb, I have had the carbs out of every stihl 0 series saws through the years, they will all seal tight without a gasket.
knoxman
ArboristSite Lurker
okay, thanks, that makes sense.
I have that metal ring in the intake boot... perhaps my gasket wasn't what fixed it. I did remove the fuel vent flap (inside the tank) at the same time. and washed the air filter with soap and hot water.
earlier it had symptoms of an air leak, or sucking air, where it would idle fast and erratic or die out, like when your tank is empty. perhaps my idle problem has been related to a failed gas tank vent and/or stiff fuel pickup all along.
when I first got the saw, the L was set at 3.5 turns (?!), and it would take 30 pulls to start; in retrospect, I guess that was done to compensate for the hard start, failing to realize that choke not fully closing in "start" position. the off/on/choke switch didn't fully close the choke unless held down. I recently bent the choke actuator rod so the choke is properly closed in "start" position now, and L is 1.5 turns.
Anyway, it was above freezing and sunny today; I ran a couple tanks of fuel through the 034 and it was running well for the first 4/5 of the tank.
I have that metal ring in the intake boot... perhaps my gasket wasn't what fixed it. I did remove the fuel vent flap (inside the tank) at the same time. and washed the air filter with soap and hot water.
earlier it had symptoms of an air leak, or sucking air, where it would idle fast and erratic or die out, like when your tank is empty. perhaps my idle problem has been related to a failed gas tank vent and/or stiff fuel pickup all along.
when I first got the saw, the L was set at 3.5 turns (?!), and it would take 30 pulls to start; in retrospect, I guess that was done to compensate for the hard start, failing to realize that choke not fully closing in "start" position. the off/on/choke switch didn't fully close the choke unless held down. I recently bent the choke actuator rod so the choke is properly closed in "start" position now, and L is 1.5 turns.
Anyway, it was above freezing and sunny today; I ran a couple tanks of fuel through the 034 and it was running well for the first 4/5 of the tank.
With the metal ring in the boot there is usually enough of the rubber left protruding up to where the carb buts up against the rubber making a seal as long as there are no cracks or bits of rubber missing. I mostly post about this sealing problem due to many times I have been contacted about the carb not sealing and if there is supposed to be a gasket there. When others in the future read these posted threads they see that you fixed the leak because the gasket was missing it gives them the idea that there should be a gasket there, they make one ,it solves their problem and they they post that same fix as being the gospel and it snowballs from there. The missing ring has been the cure for the majority of cases of air leaks that I have encountered, but one time I remember a case where someone had damaged the boot,likely when trying to reinstall it back through the bulkhead of the airbox by pulling it in with needle nose pliers the lip got distorted and ripped bits of rubber off. The owner had loaded the lip up with silicone and mashed the carb back in place, likely sealed the area for a bit but the silicone soon let go from the rubber and the leak reappeared.. If the boot is in good condition with the ring in it then a good seal is accomplished every time. Good to hear your saw is back in operation, it does sound like it was running lean from your description and I hope it is airtight now so no more damage happens, that is one reason I highly recommend using a vacuum test before running repaired saws, test the whole saw and the carb ,doing so prevents a lot of expensive damage after repairs.
If this carburetor has the plastic plate that contains the inlet needle, start looking for the newer model carb without it. These were so much of an issue that they were discontinued in the 80s.
merc_man
Addicted to ArboristSite
Well this sounds like a common problem. My 034 doesnt idle worth a crap either. Gonna have to try some things mentioned in here to see if it helps. Gonna start with a fuel line and see what that does.
I had it out this morning and when i firednit up had to adjust carb few times then it sems to run decent. Just like i hit a light switch the idle jumped up. This saw has been a pain since i got it few years back. It passes pressure vac test as well.
I was looking up a fuel line and it looks like same one as a 038? Is this correct?
I had it out this morning and when i firednit up had to adjust carb few times then it sems to run decent. Just like i hit a light switch the idle jumped up. This saw has been a pain since i got it few years back. It passes pressure vac test as well.
I was looking up a fuel line and it looks like same one as a 038? Is this correct?
SteveSr
Addicted to ArboristSite
These had Zama carbs with the somewhat notorious sticky main nozzle check valve. If this is leaking or getting stuck it WILL cause idle problems. I changed the main nozzle on my C4 carb and it has been running fine ever since.
