Stihl 034 super presence lever operation

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Gustafarian

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So I just bought a 34 super. The master control is a bit tricky cos I think the contact spring needs replacing. Anyway tends to stop when I am not cutting. I think the master control slips to off. One thing I don't understand is What the function of the presence lever? Can I put the saw in the ground or take my hand off the handle when idling and will it still run?
 
It’s definitely worth getting a new contact spring and carefully installing it. High use 1125s sometimes wear out the other components including the master control switch, operator presence lever, and throttle. You’d be safe getting a new spring first and then carefully removing and cleaning all other parts (master control can stay in the housing, trigger components can be cleaned by removing a screw in the handle and taking off the handle cover).
Usually 1125s with shot springs don’t turn off with the master control lol.
Post some pics if ya can.
 
So. I had just got it back from being serviced, prior to my post above, and I thought they would have sorted out any carby or elec issues. Cut a load of wood, had trouble with it stopping when idling. So I had a look today and made this video. I had a look at the contact operation and it actually looks like it holds the 4 positions quite well. See photo. However when I have started it and give it a run in the video - it just dies. I realise it is dirty - just cut a load, but the air filter etc should be fine. Is there an easy fix or just take it back to the shop. It is a bit of a pain at the moment with the COVID-19 restrictions in OZ and I would prefer to fix it myself. The service docket says:
Remove and clean carby
Replace carby diaphram and gaskets
Remove and clean fuel filter and inspect fuel hose
Run and tune.
Video here:34av super bogging down

Any Ideas?
 

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Yeah, man — don’t run that saw yet. It may be as simple as a carb tune, but I would personally go through the fuel system and check everything I can. Post pics here and download a service manual.
What exactly did the shop do? If you’re comfortable pulling the plug and replacing with a new NGKbpmr7a, you can also take a look at the cylinder wall for scoring. A good baseline for older saws is eliminating the common issues to ensure fuel, compression, and spark.
 
So. I had just got it back from being serviced, prior to my post above, and I thought they would have sorted out any carby or elec issues. Cut a load of wood, had trouble with it stopping when idling. So I had a look today and made this video. I had a look at the contact operation and it actually looks like it holds the 4 positions quite well. See photo. However when I have started it and give it a run in the video - it just dies. I realise it is dirty - just cut a load, but the air filter etc should be fine. Is there an easy fix or just take it back to the shop. It is a bit of a pain at the moment with the COVID-19 restrictions in OZ and I would prefer to fix it myself. The service docket says:
Remove and clean carby
Replace carby diaphram and gaskets
Remove and clean fuel filter and inspect fuel hose
Run and tune.
Video here:34av super bogging down

Any Ideas?

That saw sounds waaaay too LEAN at WOT. You either have an air leak or carb / carb adjustment problem.

It could also be a cracked / deteriorated impulse line. This is a double whammy! The impulse runs the fuel pump in the carb and a cracked hose would also cause an air leak.

Also pull the muffler cover and post a photo of the piston (rings at the top). This saw is VERY old and is likely suffering from leaking crank seals / cracked rubber. The fact that it won't idle could also be an air leak.

How many turns out (from lightly seated are the H & L mixture screws? I believe that 1 & 1 is the correct starting point.

The switch is NOT your problem unless it is not holding position... but you said that it was. The black wire / brass contact should be pushed in the rest of the way but is not causing immediate issues.
 
Can we go back to square 1? Note that OP said:
"Anyway, tends to stop when I am not cutting. I think the master control slips to off. "
Could be just a low idle serscrew that is set too low or the engine is running too rich at low idle. Simple carb adjustment clears it all up. Just MHO.
 
i had an 034 with a very similar issue, would run awesome, die out half way through a cut after leaning out, idle fine on the ground and then would die out... turns out it was the inlet rubber boot thing from the carb to the cylinder. it was fine until you picked up saw or revved it, which opened up a split in the rubber. The idle hunted around as well and it usually ended up dying just sitting there idling. New boot (after a few hours of diagnosis) and it was good as gold - they're on ebay etc. for a few bucks.

the video you've posted mate seems like it's running lean (as mine was above), so it could be the same thing, or as noted above maybe an impulse line, but this i would think less likely as it appears to idle fine. The rubber boot you can kind of check by running saw and tweaking the handle against the rest of the saw (which moves the AV mounts) or poking it gently with a screwdriver. if the idle changes whilst you're doing that, high chance that's your issue

you could also test the stop switch by pulling out the wire that the cut off switch connects onto, i've had a quite a few 034's and never had this issue but appears it does happen from above comments

will it idle for a long time without revving or it cuts out? doesn't sound like crank seals either but you never know, could be starving at high revs with not enough vacuum to pump fuel, but unlikely

you could also wind out all the way and reset your carb screws (or wind them out a full turn and try run it, then wind back in a full turn to try and clear it) - there may be a bit of crap in it from where it was serviced but unlikely as well if it was done properly. you could also run the saw with the air filter off, and see if it's continually jetting fuel in the intake at higher revs (some would suggest to wear glasses to do this bit..), if you see an obvious lack of fuel when it dies, then at least you'll know what the problem is

other thing maybe - does it only happen when it heats up, and will it run cold for longer until it gets warm? if so it could be the ignition failing, although i haven't seen/heard of this on an 034 (older ones are shocking..). aftermarket ones cheap if this is the problem

hope that helps
 

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