Stihl 021 idle adjustment

So I just got back my 021 from the shop. It needed a new carb new fuel filter and a new sprocket. It runs great except the idle is real low and it won't stay idling for more than a few seconds. I feel the shop I brought it to should have adjusted this for me but that's a whole nother story. This is my first chainsaw so I'm not used to tuning carbs. Is the adjustment I need just simply turning the low idle screw out a bit until it idles without dying? Thanks guys.

 

Turn the idle screw in its the LA screw. Just bump it up a tad while saw is running. But it could also be the L screw needs adjustment. It's a combination of these 2 screws to get it to idle. How far is the shop? They should of adjusted it for you. It literally won't take them a minute or two.

 

The shop is a half hour away but they're so busy. I don't really want the hassle with bringing it back. Thanks for the advice. I'll try it out. Doesn't seem too hard.

 

So clockwise to turn the idle up?

 

I love my 021. Had it for 15 years and can't kill it no matter what I put it thru. It should run fine after turning up the idle.

 

The LA screw, which is away from the other two, is the idle speed adjustment. For that one, turning it clockwise will increase the idle speed. Don't set it so high that the chain moves at idle when the brake is off. If it's not possible to get it to idle stably at a speed low enough that the chain doesn't move then you have other problems which could be low-speed mixture or a mechanical problem that requires repair, like an air leak or bad clutch spring.

The two smaller carb screws that are near each other are for adjusting the fuel:air ratio. The low-speed mixture screw affects idle and acceleration, is marked L and is closer to the cylinder. For that one, the direction you'll want to turn it will depend on how the saw is behaving, i.e. how well it's accelerating, whether it's stalling.

 

The idle must stay where it is no matter how much low or howmuch high you have put it ,
for example if the saw dont have other mechanical problems and you put it at 3000 rpms it must stay to 3000 rpms , if you put to 2500 rpms it must stay there

So if the idle dont stay but the saw run fine in high rpms then the more posible is to have problems that you must repair first and then tuch the carb screws

the problems usually are leaks from seals intake boots, impulse lines , if you dont have problems there , then take out the sprocket cover the bar and chain the sprocket until to see the clutch then take a look if the clutch springs are ok

And for the carb tuning maybe this help you a little

 

Good and better explication Jon And pantelis

 

The operator say the saw work fine
Yeah all saws with air leaks work fine in full throtle correct ??
but the saw dont work fine when iddling
so the shop perhaps stihl dealer dont check but sale the saw to a person that posibly dont have any idea for saws correct??

so the saw must first check and repair if need and then the carb must tuned

 

Yea . He may have not caught your point but, to the OP he is saying if your saw runs fine and idles for 5 seconds then slowly speeds up or slows it can be an air leak.

It can also be a too rich L adjustment loading up the saw and eventually flooding it out.

I'm still puzzled how they let it go out the door. Testing a saw before they call it good should be part of the fix. If they can't get it to idle they should send it back with a note that there is another problem...maybe just a dirty carb.

 

Thanks for the ideas guys. Funny thing is I got the saw back Monday after a month at the shop. A brand new carb was put in as well as a new fuel filter and new sprocket. It ran and idled fine the day I got it back. Cut some wood with it that day. All was good then I went to use it the next 2 days after and it starts and runs fine just won't stay idling for more than 5 seconds. I'm hoping I can just adjust the LA screw and all will be well but I won't know til I mess around with it today. I would think that if there were other problems with the saw the shop would have discovered them and let me know.

 

What was the temperature then...what was it the day your running now? If it was say 20 to 30 degrees difference that will cause the saw to flood out when hot when it ran fine in the cooler temp??

 

It was def cooler the day it ran good but not a whole lot diff. Maybe 10 degrees. It was more humid the days it wouldn't idle good.

 

Good Chance maybe they ran the saw early morn and tuned it then? I don't know. Bum the LA up and iF that still doesn't work. I would mess with the L screw and probably turn it in a 1/8 and see what that does.

 

Are you sure that they put a new carb ?? ohh maybe you tell me that they give you the old so you are 100 % sure that they put a new ............................................... just saying

 

If they don't they will just find an old carb laying around the shop!! Hahaha

 

some dealers here use aftermarket parts carbs and many others but they use the dealer name for selling them with the oems prices , i have see aftermarket carb in a box of stihl the customer pay for it 60 euros then i show him the carb on ebay that cost 17 dollars

all theese maybe tell you something ..............................

 

I can't even beleive that! Something like that is fraud and punishable by law!

 

Well I messed around with the LA adjustment and it still wouldn't idle long so I tried the L adjustment. Sure enough a half turn out and she idles perfectly. I feel like the shop didn't take the time to tune it right. Oh well. Wasn't too hard. Thanks guys.

 

And the new carb they put in is a genuine stihl carb.