Stihl 041AV carb

[turnkey4099]

Puzzled. I purchased this used a few years back. Not coming up to power and wanting to 4 cycle. Cleaned the filter with some improvement. Has fresh fuel with premium gas. I can only find one screw adjustment which appears to be nothing but the idle speed. Is this one of the EPA disaster carbs with no adjustments? I thought this saw was old enough not to be in the affected years. I have been using saws since 1976 so am not a novice.

Full ident is 041 AV SUPER electronic. The one screw is on the right side just below the filter cover.

Harry K

 

[treeclimber165]

There should be two jet adjustment screws on the carb, usually on the same side as the idle adjustment screw. Not familiar with the 041, but virtually every 2-cycle engine I have ever seen had high and low end screw adjustments (untill the EPA screwed things up). When you find them, see the thread titled "Won't Idle" for a basic description on adjustment.

 

[WRW]

Get a flashlight. Looking straight toward the LA screw, gaze right. On the side of the carb and up a little higher are two screws. Top screw should read H.

 

[Fish]

This saw is notorious for loose intake screws, as there is a
large stack of junk and gaskets at the carb. Also check the
fuel and impulse lines before resorting to carb adjustments.
Also check the innards of your fuel filter, as the foam inside
deteriorates over time and collects in the carb.

 

[treeclimber165]

good point, Fish


I forget that some people will go straight for the adjustment screws before looking for other causes of their problems. I wasn't thinking, just assuming that fuel lines, filters, intake mounting screws/bolts, etc. would be checked first. But I grew up in a service station so that stuff is second nature to me. I don't mess with carb adjustments untill I rule out most other causes first.

If the carb adjustment was fine last week, then it is probably fine today. Find the problem before creating a second problem!

 

[turnkey4099]

Thanks guys. Was out with it today cutting 30" log. Ran just fine once in the cut. sounds odd when revving no-load.
This one has just a flat (dished) type hard filter, no foam.
Once the filter is off I am looking only at the carb throat. To see more, I would have to dismantle the plate the filter attaches to plus part of the engine shrouding and handle attachment.
I can still see only the one screw.

This is all academic tho, as except for a quick tweak in the field with my saws anything else goes to the local small-engine mech.

Any one have a URL where I could get info on this old machine? Stihl doesn't list it anymore that I have been able to find.

Harry K

 

[stihltech]

041

Have fixed many carb problems with intake gaskets and crank seals. That is the way I was taught , the bottom must be air tight before the carb will work right. Fish got it right , intake gaskets and pulse hose on an 041 are the first places to go.

 

[WRW]

Treeclimber,
Turnkey stated that he is no novice. I guess we took him at his word.
Fish & Stihltech,
Not having anywhere near the expertise of either of you, I have to ask how any of the other problems cited could cause a rich condition as described?
Just curious.

 

[stihltech]

041

Plugged air filter, leaking inlet needle, inlet lever too high, mix screws too far out, inlet lever sticking, worn fixed jet, leaking welch plugs, inlet spring weak, leaking diaphragms, sawdust on top of diaphragms, late timing, and weak spark for starters.

 

[turnkey4099]

Yep, and as it turned out, the dirty air filter seems to have been the basic problem. Again thanks for the heads up on things to watch for in the future on an 041

Harry K

 

[WRW]

Thanks, Stihltech, for the reply. Guess I got thrown by the gaskets.
Turnkey,
That saw is an oldie but goodie.

 

[stihltech]

basics

Start with the basics every time. It will fix 90% of the problems.