Stihl 020 AVP EQ rebuild

[GeirA]

Looking good. Make sure you remember which needle went where (L & H). It's probably marked on the carb body, but sometimes it's not....

Luckily, the L & H are different sizes and only fit in their correct space. It's also marked on the carb body.

Another thing you can do while waiting is pull the muffler and make sure it's clear. These saws have a tendancy to run a little snotty and a carboned up muffler/spark arrestor can effect it's (saw's) proper "breathing". The spark screen can be cleaned up with a small propane torch by burning off the carbon build up. Let it cool and tap it off. Finish with a wire brush.

Thanks for reminding me. I had it taken off and placed aside to get it done, but for some reason it had sliped my mind. Not good

So you're saying you get good, crisp spark with the recoil cover on, but nothing with it off? Not really a problem for running it I guess, just in the diagnosis phase. Can't think what would prohibit spark w/o a cover in place..........

Yep, that's correct. It won't matter when it's back together, but being who I am, I'd like to know why it's the way it is... I can't for the life of me figure out why it's behaving like this

 

[adkranger]

Not sure what to say about the spark diagnosis thing. I've never done the drill-thing, but have spun many a flywheel by hand to test spark (plug out, connected into it's wire and a jumper wire connected from the electrode to the saw). Even by hand spinning I've received spark. Maybe your drill just doesn't spin fast enough.

 

[GeirA]

Slow couple of days

Last couple of days have been slow going due to a very bad back. Managed to get around to splitting the muffler today and unbolting the recoil housing for a good cleaning. The muffler looks in great condition and the housing will clean up easily in a wash.

I'm very conflicted in one matter:
Should I split the oil tank and gas tank?? I definitely should split the gas tank because I can see crud in there. The oil tank is more of a question because I think it's sealed ok. I'm only worried about getting them sealed back properly.

 

[adkranger]

I would not split the tank. Why bother? You can clean them very well w/o splitting the case and worrying about resealing. Empty whatever you can, let dry, then blow out what you can with compressed air. If there is still crud in there rinse with some old mix and attack with long shank Q-tips or whatever else you can get your hands on to reach those nooks & crannies. Dump out and re-rinse. Continue until clean. I'd stay away from Carb cleaner in there, can attack the paint and case seals......creating more of a problem than fixing.

The muffler don't look so bad. Some carb cleaner and a small wire brush, should clean up nicely.

 

[GeirA]

Curious

Just had a good think-through and this came up:

The carb I took off my 020 AVPS, is marked WA 86A
After ages of searching and more searching, I finally found a list of Stihl saws and accompanying parts. The AVPS is listed with WA 86D, which conforms to the details of my carb, except that it's marked with an A not a D

The manual says there should be a suction chamber diaphragm (SCD), and that the kit I need is K10-WAT (which is the one I got). The kit I received does not contain a diaphragm like the SCD in the manual. I've kept the old parts and luckily the SCD from there is in good shape.

Is this normal or should I shoot a mail off to the shop (Mowers4u.com)?
A pic to detail my not-so-easy-to-understand explanation:

 

[GeirA]

Diagnostitian needed

I've contacted the dealer and got word that the Suction Chamber Diaphragm is no longer included in the kit(s). Ah, well. Lucky I had the old one.

I've cleaned the carb, put in new diaphragms and gaskets and new impulse line. Still no luck. The saw will happily run when fed mix straight to the carb, but will not get it's own. I've checked the impulse line and I can feel it working. The H/L and idle screws are set to factory defaults (1 1/4 turn).

The fuel line I'm using now is not original/OEM, it's just normal fuel line. Sorry for this noob question but: is it required to have a seal in the hole where the line enters the tank, to get "suction"? I know it's required to not spill, but in order to test I've only filled mix to below the hole.

Starting to feel a bit stuck now Thanks in advance!

 

[adkranger]

No, you don't need a seal on the fuel line into the tank to draw fuel. But you really should have received a new metering diaphram in the rebuild kit!! Have never gotten a full kit without one. I think you were given a line of BS. What kind of condition is the old one? It must be supple and not deformed. They tend to get stiff and deformed with age.

When you pull the carb, is it dry inside? If it's full of fuel it's probably a clogged jet, if dry, well, your not drawing fuel...

Edit: re-read the post(s). If those are the pieces you received in the pic to replace the piece above, I'm thinking wrong kit. See if a sponser can't help you out with the proper one.

 

[GeirA]

No, you don't need a seal on the fuel line into the tank to draw fuel. But you really should have received a new metering diaphram in the rebuild kit!! Have never gotten a full kit without one. I think you were given a line of BS. What kind of condition is the old one? It must be supple and not deformed. They tend to get stiff and deformed with age.

When you pull the carb, is it dry inside? If it's full of fuel it's probably a clogged jet, if dry, well, your not drawing fuel...

Edit: re-read the post(s). If those are the pieces you received in the pic to replace the piece above, I'm thinking wrong kit. See if a sponser can't help you out with the proper one.

The metering diaphragm was there as well as pump diaphragm. The only thing that had been discontinued (at least from the K10-WAT kit) was the suction chamber diaphragm. The old one was in good condition, so no real loss.

According to the Carburetor Application Guide K10-WAT is the correct kit for the 020 AVPS / WA 86D carb.

I also found the "manual/illustration" for the WA 86D (link page 35).

At work right now so can't have a look at it. I'll do a test when I get home. Put mix in and pull it a few times. Then pull it apart and open the carb. I just remembered that when I rebuilt it I didn't pull the valve jet.. I left it in and soaked the carb-body (with the valve still in) for two days. I guess with the ammount of gummed fuel that was covering the screen/strainer, I should take out the jet (if I can figure out how) and give it a good going over.

Thanks againg, sir!

 

[adkranger]

OK, I understand now.

Yeah, probably worth taking the carb down again to thoroughly clean everything. You'll be glad you did in the long run. I do every time I rebuild a carb now. Nothing worse than screwin' around with a cruddy carb. Yankin' on the rope and twistin' on adjustment screws is no substitute for a good cleaning. Take note of how much fuel is in your carb.

Oh yeah, get back to work.

 

[GeirA]

Doesn't look good..
I've now pulled it apart and found the carb dry.
No wonder, as I had switched the placing of the suction chamber diaphragm and pump diaphragm. Fixed that and tried getting the valve jet out (no luck). Went over the thing with a fine-toothed comb and a cats whisker, no plugs to be found.

Put it all back together and did one alteration. I pulled the fuel line through the tank and used a small syringe in the other end as a micro-tank, to better see what's going on. As I pulled the starter the first couple of times, I could see air in the syringe as to say fuel did get in to the carb. I then poured mix into the carb to kick-start it, and for a split-second it sounded like it would go but no such luck. Only burned the mix I put in.

Went back in and pulled it completely apart once more. No mix running from the carb, only in/around the intake boot. Metering diaphragm was bone dry and I couldn't notice much on the pump diaphragm either.

Seems like the impulse is working as it looks like it's sucking in fuel at first, but I can't really say. I thought I'd at least have mix in the pump chamber.

Hate feeling stuck like this, and not having all possible tools at my ready...

 

[GeirA]

Light at the end of the tunnel?

I think I've thought about this one to death and back. Had a bit of a work done today, and I've now had the carb apart once again. Every possible passageway accessible has got another good going over. I've also changed out everything. Needle (even though the old one looked great), lever (old one also looked great), pin... Everything has been changed.

Put it back together and been thinking of a way to "test" it. Impulse line tested, by covering the line with my finger and feeling for action while turning the crank; OK. Put the impulse line on the carb and put on a fuel line. Tested again by checking if there was action on the other end of the fuel line, while turning the crank; OK. I can feel the fuel line working well and sucking like it should.

I guess all I have to do now is put it all back again (as much as needed to test) and see how it works this time

 

[GeirA]

It's alive!!!

Finally!! The beast runs
It doesn't run well, mind you (needs fine-tuning), but it runs.

I'm chuffed to bits right now, smiling from ear to ear

I'll make a quick video of it running... If I get it really running that is.
Right now I'm just so pleased it runs, I've decided to not play with anymore today. Got the early morning shift at work tomorrow so lots of hours to "play".

 

[adkranger]

That's great! Persistence pays off. Glad you stuck to your guns. Too many give up well before the steps you took and stick 'em in the dumpster.



I picked up an old 015 last week and went through it all. No spark, dressed and reset the points. Got spark. No fuel, rebuilt the carb. Got fuel. Got it to run briefly, then no go. Hardly pops. Hmm, spark & fuel stihl good, go to compression check..........90psi. It was about 135 before everything loosened up. Pull the cylinder, see what I believed was a fair amount of AL transfer and the piston skirt is worn badly. Figured I'd give it the muratic acid treatment to try to salvage the cylinder at least, what appeared to be transfer was actually the lining worn through. P/C thrashed, rest of the saw is in very good shape. Now I've got decisions to make on this $5 saw, part it out or try to find a decent P/C?? The stuborn fixer in me says to make it go again, plus I could always use another backup climbing saw. So it sits in pieces in a box till I find parts or get sick of looking at it.......

 

[GeirA]

That's great! Persistence pays off. Glad you stuck to your guns. Too many give up well before the steps you took and stick 'em in the dumpster.



I picked up an old 015 last week and went through it all. No spark, dressed and reset the points. Got spark. No fuel, rebuilt the carb. Got fuel. Got it to run briefly, then no go. Hardly pops. Hmm, spark & fuel stihl good, go to compression check..........90psi. It was about 135 before everything loosened up. Pull the cylinder, see what I believed was a fair amount of AL transfer and the piston skirt is worn badly. Figured I'd give it the muratic acid treatment to try to salvage the cylinder at least, what appeared to be transfer was actually the lining worn through. P/C thrashed, rest of the saw is in very good shape. Now I've got decisions to make on this $5 saw, part it out or try to find a decent P/C?? The stuborn fixer in me says to make it go again, plus I could always use another backup climbing saw. So it sits in pieces in a box till I find parts or get sick of looking at it.......

Thank you sir! Always good to get some positive comments.
This thing will cut again, I don't care about the cost.. It's personal now

I think I have an air leak someplace (most likely boot or manifold, if I remember correctly from researching Stihls). It starts up in anywhere from 1-4 pulls and runs (stihl can't get it adjusted 100%). Then I release the throttle and it idles a bit then dies. Seems obvious it's got to be an air leak. Got some more investigating to do, but it WILL run. I'm planning to put either a 16" or an 18" on it, depending of how it operates.

I hope you don't get tired of looking at it! Did a quick search on fleabay, and found a stihl 015 (starting at $19.99, $24 flat rate shipping). Looked to be loads of parts for 015 (P/C combo $40) on there.

Hope you get it sorted and to see a thread on it :biggrinbounce2:

PS! How does the rep thing work? Like; How many do I have to rep in order to rep someone a 2nd time? Tried to rep you now for your invaluable input, but it said I had to spread it out more. (Been rep'ing mucho lately).

-Geir

 

[adkranger]

Oh, I'll probably get the 15 going again, (did I mention I'm stubborn?) just have to find a decent P/C for reasonable $. Should have done a thread on the tear down, but I'm a bit ADD right now and have three saws in various stages of assembly. Can't figure out where my priorities are I guess, but it's a hobby, stress reliever so I just pick up what I feel like at that time. I already have a full stable of runners.

On your 20, after revving it, it idles for a bit then dies? Does it just sort of tail off? Or does it rev a little erratically before stalling?
Could be an air leak at the manifold. Check the mating of the carb to the manifold and manifold to intake port on the cylinder. Make sure to torque the screws down enough to seat it, just be careful not to over do it (steel screws & AL cylinder). Also, if you've been able to run it a bit, check the plug. Specifically the color of the electrodes. (Light brown = good, black/wet = rich, white/grey = lean)

Don't know about the rep # game, but you've got me once. It's all good.

 

[GeirA]

Oh, I'll probably get the 15 going again, (did I mention I'm stubborn?) just have to find a decent P/C for reasonable $. Should have done a thread on the tear down, but I'm a bit ADD right now and have three saws in various stages of assembly. Can't figure out where my priorities are I guess, but it's a hobby, stress reliever so I just pick up what I feel like at that time. I already have a full stable of runners.

On your 20, after revving it, it idles for a bit then dies? Does it just sort of tail off? Or does it rev a little erratically before stalling?
Could be an air leak at the manifold. Check the mating of the carb to the manifold and manifold to intake port on the cylinder. Make sure to torque the screws down enough to seat it, just be careful not to over do it (steel screws & AL cylinder). Also, if you've been able to run it a bit, check the plug. Specifically the color of the electrodes. (Light brown = good, black/wet = rich, white/grey = lean)

Don't know about the rep # game, but you've got me once. It's all good.

I know exactly what you mean. I'm stubborn as h... also.

I start it and rev a bit on the throttle. Trying to adjust the carb at the same time. Then when I release the throttle it'll sometimes idle a few seconds and sort of tail off. Sounds like it runs out of gas, which is why I'm thinking air leak. I've got it sort of apart now, to mess with the fuel line and starter rope (too short). I'll have another look through the manual and stuff to see if I'm missing a gasket or something. There was no gasket when pulling it apart, but last guy who had it open forgot to put back the air filter and a few other bits, so I wouldn't put it past him.

I'll change out the spark plug to a new one and have a go when it's back together. Looks like I'll have some time to tinker and play, as my colleagues and I just went on strike 06:00(CET) local time.

 

[GeirA]

Here's a video of this thing running. I'm only running it to let you hear/see what's going on with the idle. The B&C's been misplaced so I'll have to look for that tomorrow before I can do any more tuning and running.

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[stihlman32]

Sorry if I missed it from an earlier post, but have you set the LA screw yet? This controls how open the butterfly valve will remain, after you let off the throttle allowing it to idle. Thats probably the easiest starting point. Once you get idle then you can tweak the H & L screws to spec.

EDIT: Standard adjustment for the LA screw is to turn CW until the chain begins to move, then back off 1/4 turn.

 

[GeirA]

Sorry if I missed it from an earlier post, but have you set the LA screw yet? This controls how open the butterfly valve will remain, after you let off the throttle allowing it to idle. Thats probably the easiest starting point. Once you get idle then you can tweak the H & L screws to spec.

I've tried the idle adjusting screw, but didn't help. That's one of the reasons I'm suspecting it has an air leak. One thing I haven't done is change the "clamp" fixing the boot to the intake port. I guess I have to have a better look at that tomorrow.

 

[stihlman32]

What is your setting for the L screw? Air leak likely if you L screw is way out past factory spec. Standard setting for both L & H is 1 turn open.