025 problem adjusted carb, changed filter still runs bad

[West Texas]

I'd try turning the LA or idle clockwise a half turn or more; and, turning the L low jet clockwise an 1/8th turn. Just don't get the L too lean.

 

[Lakeside53]

I'd try turning the LA or idle clockwise a half turn or more; and, turning the L low jet clockwise an 1/8th turn. Just don't get the L too lean.

I think you mistyped? Turning the L screw clockwise will lean out the mixture... I think you mean "counter-clockwise".

 

[stihltech]

problem

#1 throw away the compression guage, it will only confuse you.

Pick it up by the starter handle. If the saw comes up with it or unwinds very slowly, compression is OK.

My bets are on the fuel or pulse hose. As for the carb, you may still have a piece of something in it.

Hoses first.

 

[Lakeside53]

Crank seals doesnt sound like an easy job - just a guess.

It's "moderately" easy IF you have the Stihl oil seal remover. Most don't have it (dealer cost of about $120) and try to use a a screwdriver or whatever, but on the 21/23/25 you can't get into the clutch side without the right tool without taking out the motor. BTW, it's quite uncommon to have a seal failure on these small saws. I've only seen one in two years, and have seen a lot of these saws.

 

[West Texas]

Lakeside53

Nope, I meant what I wrote, as a rich mixture will help start the saw; but, if its too rich it may later stop. Sometimes a slight inward clockwise adjustment will perk up the rpm's to the right point. At least that's been my experience on Stihl carbs that are fully adjustable. But, that's just my experience, could be wrong again.

 

[Lakeside53]

hmmmm... o.k. we agree that in is leaner, and out is richer. Turning the L screw leaner will perk up the rpms, but makes it harder to transition from idle to high power. Sure, if it's too rich it will cough out at idle when it gets warmed up, but that won't stop the throttle transition to high which is the reported problem, and that's where the LA screw is used to compensate. Generally, and there is much written all over this site on the topic, you need to find a balance between good transition from low to high, and warm idle. Generally, make them as rich as they can be when warm (within an 1/8 turn of std), and use the LA screw to keep them running. The tests I always perform are : idle speed, and 2) transition. Too lean on idle will give you that pause or cutout when accelerating.

My 2cents, whatever that's worth today.

 

[Diesel JD]

Thanks for all the thoughts guys. Replacing the fuel line I need to take it out of the tank and off at the carb, is it that simple or more to it? Thanks!
J.D.

 

[Lakeside53]

it's dead simple... you MIGHT have to remove the carb to make it easier but it's not essential. The hose is keyed so it only fits one way.

 

[Diesel JD]

So I should just go to the Stihl dealer and ask for the fuel line rather than trying to make one out of the correct diameter small engine fuel line? Thanks,
J.D.

 

[Lakeside53]

yes, it's a custom moulded line. Should cost you about $7.50. Make sure the old one is bad first though.

 

[West Texas]

Lakeside53

Sounds to me like you and I do about the same carb procedure; and, have some of the same saws. I find getting that balance between L and LA gives you a good idle and great accelleration too. Then I fine tune the H when its in the cut, for best torque performance. I don't have a tach, but, this technique seems to work for me.

 

[buck futter]

I have a 025 that runs great for the most part but sometimes after i put it down and idle it will stall if I pick it up to quickly or roughly, if I pick it up with kid gloves its fine. My first thought is maybe it is a little rich on the low speed I did the test of flipping over saw to see if it loads up and dies but it always idles the same and only will stall when I do as described above. maybe I am just to picky.

FWIW your information has been top notch and its great to see all the involvement with this guys problem

Lucky

 

[Diesel JD]

How would I make sure it's bad? Just visually check it fopr cuts, nicks? or something else. As lucky said, you guys have been great. I appreciate y'alls patience and good advice. I did what STihltech said about picking it up by the starter handle. The whole saw came up with it, and it unwound very slowly....from his description, probably means I have OK compression. It may be like Lakeside said that my gauge is all wrong for small engines. That said it must either be seals or fuel system. I guess I just have to find out which one. Is there anything else it could be?

 

[Lakeside53]

take it out and visually check it (look for cracks and holes), or, like I suggested previously, by pulling the hose off the carb and pressurize the hose and tank with a bicycle or any small bulb pump. You'll see it leak... spray soapy water on it and watch for bubbles.

 

[Lakeside53]

I have a 025 that runs great for the most part but sometimes after i put it down and idle it will stall if I pick it up to quickly or roughly, if I pick it up with kid gloves its fine. My first thought is maybe it is a little rich on the low speed I did the test of flipping over saw to see if it loads up and dies but it always idles the same and only will stall when I do as described above. maybe I am just to picky.

FWIW your information has been top notch and its great to see all the involvement with this guys problem

Lucky

Lot's of possibilities here...
You could have a carb boot problem (cracked), bad fuel line, a bad impulse hose (cracked), or, the metering diaphragm in the carb is distorted and/or the metering needle is set wrong. Basically something is being affected by the G forces resulting from the sudden motion... If it dies suddenly, then it's likely get a blast of gas and getting too rich. If it winds up then dies out, it's getting leaned out. Could also be some stupid electrical problem with the grounding wires.

 

[Fish]

It is a molded fuel line, but it can be put in wrong. The wide part that presses into the fuel tank has a straight edge, which shoild be to the left side, parallel with the
side of the saw.
It usually cracks on the side above the tank, so just look at it. if you see moisture from fuel in the area, that will usually tell you quickly if it is bad.

 

[buck futter]

lakeside,
Thank you for your reply, the saw dies as if it is running rich, the whole story is I swapped a fixed hi jet carb with a fully adjustable carb I had to mess with it a bit to get it to run fairly well but it made a huge difference in performance. contrary to what the trend was my fixed jet carb was overly rich verified by the black sooted plugs and it would never top out. The difficulty with the new carb is it would choke out to rich with the standard jet settings I had to set the lo speed closer to 5/8 - 3/4 of a turn out instead of 1 full turn. The hi speed seemed to work ok. So many problems will show a lean condition but very few act rich? I believe the inlet lever is set right (level with the bosses) the diaphragm looked ok but maybe I will try switching it. I did change out the main jet but it seemed ok. I'd love to hear your advice.

Lucky

 

[Lakeside53]

So, apart from running rich, did the saw work fine before you changed out the carb?

Did you use a fully adjustable carb FOR an 025 or did you just make another fit? exactly what carb number/manf. did you use? Usually I see the fixed jet carbs run lean, not rich.

off to work. I'll back on tonight.

 

[buck futter]

http://www.arboristsite.com/showthread.php?p=305884#post305884

This thread basically outlines the situation, yes the fixed jet carb ran fine. I bought the saw when I worked for a dealer down by the coast. Then I moved up to a higher elevation. Maybe its a possible explanation. For the most part the saw rips now and I am quite happy but something is not perfect.


Also I understand that these saws are not worth having a dealer replace the rings or piston. If I ran it a few more years and wanted to re ring it myself how much are the internals for this saw and for the price of parts would I be sitting better than buying a new saw?

thanks
lucky

 

[Lakeside53]

I''m a little confused... your referenced thread shows that you had it running fine after replacing the main valve. Now it's still rich?

your other question : no it's not economical to have a dealer do the work. It's a real pain as the entire engine has to come out. The piston/rings/pin are about $72 and about two hours of labor at shop rates make it an expensive rebuild for a little saw. However, it can make sense to do your self if the cylinder bore is o.k. I'd be surprised if you ever wear it out (keep the air filter clean, don't over heat the saw)....