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Eagle_Adam

Forum smart but 2stroke stupid....
Joined
Dec 15, 2018
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Location
Portland Oregon
Hey guys,

Before I take the saw to a shop I’m hoping some of you would be willing to grace me with your opinion.

The saw - Stihl 041AV electronic

The issues/symptoms:
- slow to accelerate
- Bogs to a stop when it hits wood


I’ve done:
- carb clean
- fuel/air filters cleaned
- carb H&L screws turned till seated and backed off accourding to the manual
- idle screw adjust both ways to no avail
- muffler screen cleaned
- fuel lines visually checked
- pulled plug to verify spark



Sooo... opinions on what I missed/overlooked ect?
 
Have you tried adjusting the H screw to other than the factory recommended setting of 1 turn out? If not, I would give that H screw another 1/4 turn out and see if that changes anything. Those factory settings are just a starting point to get it running so you can tune it proper. Like pioneerguy600 I too am curious how your compression is on this saw. If it idles good and bogs immediately on pulling the trigger you may be okay on compression and just a little lean on the carburetor H needle setting. This would also explain why it falls on its face when you try to cut with it. When you start making changes to settings, let us know how it reacts to those changes. That will help us to help you figure out what's wrong.
 
I'd pull the muffler & look at the p&c. A bit of a bear on the 041 but it'll tell you something.
If you have a Mityvac, clamp one end of your fuel line and pump it to about 10 psi. Make sure it holds and it's not bubbling out somewhere. Sounds like your carb isn't getting enough fuel or it could be too much air getting in somewhere else. Pressure test Bad seals, worn cc gasket or even the carb flange block can be leaking.
When you say carb clean do you mean rebuild or just spruced it up a bit? And what did you clean it with. Did you inspect the diaphragms, the inlet needle and the gaskets? When you resealed it and primed it with some gas, does it hold 10 psi without leaking?
 
Have you tried adjusting the H screw to other than the factory recommended setting of 1 turn out? If not, I would give that H screw another 1/4 turn out and see if that changes anything. Those factory settings are just a starting point to get it running so you can tune it proper. Like pioneerguy600 I too am curious how your compression is on this saw. If it idles good and bogs immediately on pulling the trigger you may be okay on compression and just a little lean on the carburetor H needle setting. This would also explain why it falls on its face when you try to cut with it. When you start making changes to settings, let us know how it reacts to those changes. That will help us to help you figure out what's wrong.

I’ve messed with both of the screws & the idle setting fairly significantly
 
Haven’t checked yet. The adapter should be coming in today or tomorrow chose to wait for one that works with my pre-existing kit

Feels decent to me though, not that that really means anything

If the comp turns out to be fine then there are a lot of gaskets between the carb and engine, all need to be air tight. Carb itself needs to be correct, always a question there.
 
Look at the huge stack of crap between the carb and block. **** rattles loose under there and leaks air into the system and really screws with the air/fuel mix. Look for a lot of loose screws and torn gaskets, fix with blue loctite and new gaskets. Also look at the impulse line.

Impulse line??

I’ve checked the boots and gaskets between the cylinder visually, and I have sprayed carb clean around them to see if I can get the motor to race indicating a leak.
 
I'd pull the muffler & look at the p&c. A bit of a bear on the 041 but it'll tell you something.
If you have a Mityvac, clamp one end of your fuel line and pump it to about 10 psi. Make sure it holds and it's not bubbling out somewhere. Sounds like your carb isn't getting enough fuel or it could be too much air getting in somewhere else. Pressure test Bad seals, worn cc gasket or even the carb flange block can be leaking.
When you say carb clean do you mean rebuild or just spruced it up a bit? And what did you clean it with. Did you inspect the diaphragms, the inlet needle and the gaskets? When you resealed it and primed it with some gas, does it hold 10 psi without leaking?

I’ll pull the muffler and take a peak, compared to the Head gasket job I did yesterday this muffler should be a walk in the park.( famous last words..)

I’ll pressure test the fuel system as well and report back

As for the carb... i did not rebuild it, I removed it took it apart and cleaned it to the best of my abilities. Honestly I figured that since 50% or more of the vehicles I work on have carburetors and I regularly tangle with them. This should be no problem, again famous last words
 
Chainsaw carbs are really sensitive , those diaphragms need to be supple and not worn to perform correctly along with being set up correctly. Every carb kit I install has really woken up old saws that have not been active full time.
 
Chainsaw carbs are really sensitive , those diaphragms need to be supple and not worn to perform correctly along with being set up correctly. Every carb kit I install has really woken up old saws that have not been active full time.

Duly noted, so what site do people prefer to acquire Stihl OEM rebuild kits? And what should I expect to spend, I had a local saw shop quote something like 50-$60.... which is frustrating if true through, because I can rebuild most 4barrel carbs for half that -.-
 
Another point is be sure and pressure test your carb. Depending on how old it is the gaskets on the pump and metering side of the carb could have developed leaks since you took it apart. Should hold at 10 psi. If it doesn't dunk it in water and see where it leaks from.

You could try what was suggested earlier first though, tune it out a little richer (it sounds like it's lean) and see if that helps.
 
OEM kits for Stihl carbs are pretty outrageous. See what it's got and you can get a genuine kit from the carb mfg (maybe not if it's the Tillotson)
 
Duly noted, so what site do people prefer to acquire Stihl OEM rebuild kits? And what should I expect to spend, I had a local saw shop quote something like 50-$60.... which is frustrating if true through, because I can rebuild most 4barrel carbs for half that -.-

To get an OEM kit its basically through the dealer only and they are not allowed to sell or ship parts, some will but they could be heavily fined if caught. A carb kit from Stens is what I use most and they run less than $20. if they can be found.
 
041 AV it appears had only the HS-138B or 208B carburetor. I disagree about buying a new one, $20 is going to get you a Chinese knockoff, nowhere near the QC of the Tilly original. Unless the internals are toast it's worth rebuilding.
Stens is a great aftermarket vendor, but I bet you could get a Tillotson kit from other vendors too.
 
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