stihl 021 dying

[grantwolland]

I have a 021 that I believe is suffereing from carb problems. I can start the saw up and run it till its warm then it wants to die off, especially when throttled. I still get good spark even when it's dying. adjusting the carb doesn't help. any idea what carb this saw uses? and where to get a good rebuild kit?

 

[troutfisher]

Check the muffler for a plugged up screen.

 

[grantwolland]

clean as a whistle

the saw has been cleaned up, that includes air filter, plug, muffler and the inside of the housing. as far as I can tell it doesn't have anything wrong externally except on the fuel tank it has a short piece of fuel line? that has two setscrews in it. I'm assuming that is a vent line of sorts. the old line was cracked so i used a new piece of line that the screws fit into and put it on the tank vent. How does that work? the cylinder and piston on this saw are fine. that is why I'm questioning the carb because I can't find anything else when I cleaned up the saw.

 

[Bermie]

Check the fuel line from the tank to the carb (the flexible one with ridges) if you see ANY little cracks or splits, replace it. I have an 021 about 10yrs old, the fuel line has perished twice.
It would start fine, but then would not run off the choke, it was sucking air through the cracked line.
Did you clean the saw yourself? If not, don't assume that the spark screen in the muffler was cleaned!
Otherwise, look at the factory settings for the carb on the orange casing, make sure the idle is set high enough (1200rpm, sounds quite fast to the ear) Shut the saw off, turn the L screw in all the way and then back it off as much as the little diagram says, if you have an H screw do the same. That should get things working, fine tuning for performance is best left to someone who knows more.

 

[grantwolland]

I cleaned the saw myself and even went so far as to beadblast the muffler out to remove any traces of carbon. I have yet to check the fuel line. If it is busted can I use standard tygon(yellow) fuel line that matches the id of the stihl line or must I use the Stihl line and what should I expect to pay for this line? As far a carb adjusting, I have the saw running great when it is cold. It's just after it warms up it starts to act up and fall on it's face without a load. This usually takes three or four minutes(maybe?) I haven't timed it. thanks so far for the input.

 

[Bermie]

The fuel line is specially manufactured to go from the tank to the carb, it has a 'skirt' thingy that seals the hole in the top of the fuel tank, and the ribbed bit allows it to bend without kinking, the rubber is the right 'flexiness' for the hose to push onto the carb and fuel filter and hold with no additional fastenings. As for price, I don't live in the US so what we pay is like three times what you pay, but the part wasn't too expensive. Get the right part!

As for your carb settings, something is obviously not right, did you try setting it to factory like I suggested? It has to run well both at idle and full throttle no load once warm. Then when you cut it must not 'bog' down when cutting or 'hesitate' when applying throttle from idle.
Check your owners manual (yah, that little book you got when you bought it!!) for standard carb settings.

Keep at it!!

 

[grantwolland]

Thanks bermie. I pulled the fuel line this weekend and saw what you descibed. It has cracking but I'm not sure if the cracks go all the way through. I'll replace it anyway. as far as the carb, I started with the factory adjustment and went from there and I had it running well. Then once it warms up it starts to act up and further adjustments don't help so I think it has something to do externally and not the carb itself. This saw is actually a friend's I'm working on and didn't have a manual but I got one from stihl and am fairly impressed since it was of no cost to me. It is nice to find a small engine company that gives large engine support to it's products even if they do cost a bit much. I don't know If I could ever justify paying for a new stihl since I rarely make money on cutting trees. Now If I did this for a living that would be different.

 

[Bermie]

Cool!!
Hopefully the fuel line replacement will solve it, fingers crossed...
The 021 was my first saw, 10 yrs ago, still runs like a trooper and fine for small trees, pepper bashing (a nasty invasive) and the reliable spare!