Help to adjustment carburetor on Stihl 031AV

[JamesReed]

Need some help for those who know how to adjust the carb on this older model - Stihl 031 AV. I just rebuilt and have no manual to help with adjusting. It is a Walbro with a H and L plus an needle that one can adjust inward to open/adjust the throttle in more.

Here is what I do: First - Screw H and L all the way in and back-off both H&L 1 full turn. Start saw. Chain is really moving fast/oil coming out on bar. I slowly turn to the right the L (one next to combustion chamber) until the chain is almost stopped or barely moving. Next I trigger saw to test high speed. Saw bogs down when I try to rev saw up to check high speed and usually stalls out. :bang:

When and do I use the screw-in needle adjustment that can hold throttle open?.

Thanks

 

[t_andersen]

http://www.madsens1.com/sawtune.htm

 

[WadePatton]

Now that's the ticket.

What do you do when step #4 doesn't work--can't warm saw up 'cause saw won't run?:bang:

It'll run here and there, but 30-40 seconds has been tops. Maybe 10 seconds otherwise. The rest is stammer/no hit. Just had carb off, diaphram was on upside down--no fuel at all that way. Three pulls choked, then 2nd or third pull off choke and it'll stammer/putt-putt.

 

[Lakeside53]

jamesreed : you're forgetting to first set the LA screw so the saw "just" idles with the L screw out one turn (or 1 1/4 depending on your carb).... then adjust the "L", (and maybe the LA again) then the "H".

yes, look at the suggested Madsens link.

 

[Lakeside53]

Now that's the ticket.

What do you do when step #4 doesn't work--can't warm saw up 'cause saw won't run?:bang:

It'll run here and there, but 30-40 seconds has been tops. Maybe 10 seconds otherwise. The rest is stammer/no hit. Just had carb off, diaphram was on upside down--no fuel at all that way. Three pulls choked, then 2nd or third pull off choke and it'll stammer/putt-putt.

Just ignore the warm up... adjust it anyway you need to to idle, even if it means winding in the LA screw a lot before adjusting the L, then back off the LA etc... Then figure out what is wrong with your H, or maybe your impulse line?

 

[WadePatton]

So that's what it's called--impulse line.

Now that I've become a master of the linkage, I'll go back in. I replaced the fuel line, hoping that was the deal. It ain't.