Pulling my hair out, Stihl 021!

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WildnCrazyGuy

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I know, an old 021 POS, but it was my first chainsaw and is sentimental, has always run perfect, but I've been fighting this saw and I think it will still run great, but I can't figure out what it is, so I'll let you guys point me back to the basics.

The story...

Changed the fuel line in it a few years back because it had an old 16-17 year old filter on it and per recommendation, should be changed more often than 17 years. When I go to change it I can't reach it. After joining this forum back then, I decided to get me a new fuel line also. What I found is they changed the fuel line and the in the tank part is much longer than the original allowing for access to replace the filter. I struggled a bit, but figured it out and had a fresh fuel line and filter installed. Life was good.

I recently pulled it out to cut down a small tree and when I layed it on the side to cut, I was covered in gas. The saw ran just fine, but leaked where the fuel line grommet went into the tank. I thought maybe a split or something, so I got me a new line. Pulled the old line out and replaced with the new line. I found no splits in the old line, looked really good. I guess the line had shrunk a bit and didn't seal anymore. The replacement line fixed the leak. Great! Wrong.

I got the saw all put back together, leaned it on it's side checked for leakage, no issues. I go to start it, seems normal, runs a few seconds and dies.

Long story short, I've checked compression, 135, changed spark plug, impulse hose, carb kit, taken the vent off, you name it. I can get it to run a few seconds, maybe 20-30 at times, but it soon dies. It seems like it's not getting gas, which is why I changed the impulse line. Could be a carb problem, but I don't think so. I did put a new kit in, looked really clean, sprayed carb clean through anyway. Put the carb back together ok.

Here's what puzzles me. I lay the saw on the side, fuel fill up, when I set it upright again, more times than not, fuel starts coming out the fuel line where it connects to the carb. Like pressure has built up when I layed it on it's side. I'm thinking vent issue, but vent looks ok, I even pulled the vent hose off and it does the same thing.

I'm stumped. At this point I can't troubleshoot if it's a carb issue, vent, fuel line, impulse line, whatever. Remember it ran just fine before I replaced the fuel line, just leaked out the tank because of the seal. New line fixed that.

So, my next step is to take it back apart and replace the fuel line with the one that leaked to see if it runs again, then it might be a defective fuel line, I've heard of them collapsing and causing similar issues, but I don't think this is my issue, but again, I'm stumped. If it does run fine then I'll assume it was a bad line and I'll have to replace it to get a line that won't leak.

Through all my rambling here, I'm hoping someone says here is what I think you've done and here's your issue. Thanks guys in advance. I'll keep plugging away at it because I'm sure it's still a good saw. I have other nicer saws, 260 pro, 361, 441, etc. so it's not a need issue, but I would sure like to figure this thing out.
 
Thoughts...

If you pulled the vent tube right off then you've ruled out vacuum. I don't think 20 secs running would pull enough fuel to be a vac problem anyway.

If the new hose/grommet is really tight is it possible the hose is pinched inside the grommet. You could get some vapour through to get it going maybe but not enough fuel to keep it running?

Does leaving choke on help? Or adjusting L mix richer/leaner (whilst idling) - might give a clue whether it's fuel & air problem and which way it is.

I don't think fuel coming out the hose by the carb is a big issue as the fuel vaporising in the tank might create enough pressure to push some through.

Maybe carb not sealing to cylinder/split boot etc.

Hopefully someone will be along in a bit with the answer....
 
If the saw will idle and stay running but die when you hit the gas, I would recommend rebuilding the carb. The diaphram is more than likely stiff and hard from sitting with old fuel in it. Put a carb kit in it and see if it helps.
 
Did it quit on you immediately after you put the kit in? If that's the case, I'd recommend rechecking your work and adjusting the metering valve. I've done a number of wt-215s now (I'm just guessing this is what you've got), and the new one that comes in the package isn't necessarily set correctly.

If it worked ok after you rebuilt it, I'm gonna guess the carb sucked some crud...new kit, clean out all the passages with carb cleaner. Keep us posted, eh?
 
Sorry guys. Got a little off track this week. Hopefully get to working on it by this weekend. I haven't been here in a while. The board sure is active now. Go a few days and you can read through 6-8 pages of threads. That's a good thing that it's as active as it is now. So, bump... I'll try to play with it some by the weekend and report back.

No fixed jet on my old 021. I guess they might have switched in the later years of the 021 or more likely the 210. I've got H and L and they're fully adjustable. No silly limiter crap.

Saw was run empty before last use, as all my stuff is and ran great then, so no cruddy gas in there to cause me issues. I don't keep gas around long enough for it to go bad. Usually a couple of months at most. Anything older gets put in the truck and back to the gas station I go.

The diaphram was a bit stiff, but the kit I installed had a nice flexible fresh one, so I think that's good.

Metering valve looked ok and adjusted properly, level with the top of the carb. Like I said, I'm stumped, but I'll keep at it. Thanks.
 
"...fuel starts coming out the fuel line where it connects to the carb..."

SHOULDN'T HAPPEN. Means the hose isn't sealed to the spigot, means it'll be sucking in air when running
 
True enough ...

"...fuel starts coming out the fuel line where it connects to the carb..."

SHOULDN'T HAPPEN. Means the hose isn't sealed to the spigot, means it'll be sucking in air when running

I assumed he meant when he pulled the hose off the carb but reading again maybe not!
 

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