Stihl 020 AVP EQ rebuild

[GeirA]

Hi all.
This is my first post on this site, and (of course) it's a question.
I've been lurking around a bit and searched a lot!

I got a Stihl 020 AVP Super EQ from my dad a year or so ago. He said it ran great when he used it last, but it hadn't been used in a year or so prior to that. I tried to start it, but no luck. Wouldn't start.

As I didn't really need it at the time, I put it on the shelf thinking to have someone look at it later. (At that time I didn't fix stuff like this myself.)

The opportunity to have someone look at it presented itself and after the mechanic looked at it, he said there wasn't a chance he could get it going. I took it home and put it back on the shelf. Now I've decided to give my old teachings (my first education was as a car mechanic) and want to see if I can get it running.

Here's what I have so far;
I've managed to get ignition (the guy who looked at it had the sparkplug at almost 1mm gap, and it should be .5mm) and it sparks great.
I haven't taken much covers off it yet, but the lines I can see looks OK.
Trying a cold start by just dumping mix in the carb and a touch of starter-gas it fires right up and runs great with that little mix, then stops. This sounds like it can't get mix from the tank. (I've dumped out the old mix that was in it and put in fresh mix.)
From my limited knowledge it sounds like either a blocked line or the diaphragm is shot. Should I just take it apart and rebuild the carb?

Also, I've noticed there seems to be a screw missing. It's a hole marked LA (seen in picture attached). Haven't got a clue what this is, as I haven't found a manual.

From what I've read the carbs on these saws can be very .... to get running good, but as can I assume it's not much cleaning needed as it runs great with the mix I give it?; and that it's probably just the pumping that needs work/replacement?

Sorry for such a long post, but as I've read around, you guys like pictures..?

NOTE! The old red saw you see in the backround is a very old Jonsered saw (I have no idea what model it is, as the markings were ripped when I got it). I've taken it apart and fixed the ignition but the carb had a cardboard-like diaphragm and I haven't a clue as to how I'll find spareparts.

 

[GeirA]

Torn down

Well, I couldn't sit still this evening and ended up tearing this beast down to see what I could find. WOW, this thing is crazy-hard to take apart!

I've got some pics of the carb and boot + the lines. I don't think I'm wrong when asuming I've found one part of the problem.

As with any saw that hasn't been maintained too well, there's a lot of dust and oil everywhere. That'll be easy enough to fix.

The impulse line looks ok, but I haven't tested it yet.
The fuel line was amazing. The part on the carb was so hard and stiff (not to mention it was in two parts) I almost couldn't get it off with pliers! There was no real seal there so of course the carb didn't get any fuel.

Rest of the carb looks ok for now, but I'll have to inspect it closer when I get the parts cleaned out. Hmmm... Think maybe I should build me a parts washer tomorrow!

Carb, boot and rotten fuel line:

Close view of the fuel line and broken off part:

Close view of the boot:

Choke side of the carb:

Throttle side of the carb:

Now I have to find a dealer (if one exists) who can deliver the parts needed to sort this out. Most worried about the boot.

 

[Brian VT]

There's a common rant on here about how fussy the 020 carbs. are.
I have 2 saws here that I haven't bothered with yet due to the expected frustration with the carbs.
We could use some good news about them. Post back here soon that you got it running well, please.

 

[fluffysaw]

fuel hose

you might try ebay for the fuel line....I had two stihl dealers tell me its not available...but i have seen them listed on e-bay....I replaced the impulse line with regular 2cycle fuel line...its just a hose...once you have the carb number and type getting the carb kit is easy as going to a good lawn mower shop....the LA screw is a screw that manually keeps the throttle open...it should have a point on it....do a seach for carb adjustment. You could replace the LA screw by purchasing the body part that it screws into off of ebay.....without e-bay you may run it to trouble trying to locate parts...but by all means check with your stihl dealer first you never know if they have NOS parts.

 

[adkranger]

Yes, the carbs on these older 020s can be a bit touchy and general assembing/dis-assembing these old saws can be cast iron beotch, they are worth it when you get 'em going right. Nice little limbing and trimming saw.

That 020 looks in fine shape. Looks like you are doing well so far. Get those new lines on there, some fresh mix and see where you're at. Is the boot bad? Also, looks like your Idle screw (LA) is stihl right there on the carb. Not sure what screw you're missing, will take a look a the IPL see if I can figure it out.

Edit: looks like the screw you're missing is an M5x18mm Part # 9048 216 1010, then there's supposed to be a plug (9302 929 0840) in case to cover/fill the hole. Not sure what the screw secures though.....

 

[fluffysaw]

lol

Yea it is right there...i didnt even see the picture
yours is newer...Doesn't look like the same carb i have on mine the screw is on the cast alum part on the intake boot of mine above the hose connection....might want to see if that was a replaced carb

 

[adkranger]

Also, I've noticed there seems to be a screw missing. It's a hole marked LA (seen in picture attached)

OK, upon further thought, I think that screw I mentioned (M5x18) is actually the one in the upper right of your pic. You're probably just missing the plug. It's possibly an extra casting hole to accomodate different carb setups? Fluffysaw mentioned his was different. Is there something to take a screw below? Maybe that piece on the end of the boot that the carb mounts on? It's been a long time since I messed with one of these...........

 

[fluffysaw]

ADKranger is correct....I just rebuilt mine this weekend it had a tilly carb and it uses the LA hole where you think a screw is missing.
Your carb, your carb might be....wt-15a, wa-1d, or wa-86d according to the medcat i seen

 

[GeirA]

Thanks for all the replies and help so far guys
After a good nights rest I've managed to have an even closer look at the carb, and it's a Walbro WA 86A. The screw I thought I was missing is located on the cast part of the boot, but there's nothing there to actually hold a screw.

Looking at it now that I have the flywheel of and ignition exposed, it's a miracle this thing would even spark! The ammount of dust and oil there is almost worse than it was on my ancient (and yet unnamed) Jonsered. I'll have a good cleaning and I might try with new lines, cheating and using a normal fuel line, before really reassembling the thing. Just to see if it'll get mix and run.

Here are some pictures of the ignition (it's the thing below all that crud):

 

[volks-man]

the fellows above are indeed correct.
the extra LA hole is supposed to have a little black plug in it. it is simply the location of the idle speed screw for older models. stihl left it in the mold when they moved it to it's current location on the assembly seam.

please note that if you ever change to the older type carb you will need the carb mount as well. the older one had threads cut in to a protrusion for an adjusting screw. the newer mount uses a screw that is part of the carb.

 

[GeirA]

Cleaned (sorta)

As it would happen, I have a semi-normal job and that takes away from the time spent doing stuff like this. Luckily I love my job so it's not all bad; And it helps me continue to do this stuff

I couldn't find the time to make a parts washer today, and probably not tomorrow either, so the normal sink had to do. I concentrated on the crank-/tank housing and the ignition, to get that as clean as possible. It didn't turn out too bad, but there's still some crud left.

Cleaned it, dried it and tuned the ignition.
Now, I saw a tip online some place that you could use a drill and a socket on the nut of the flywheel to get ignition, but that didn't work here. (Worked on the old Jonsered.) So I put the recoil-/oil housing back on and gave it a few tugs. Success! Ignition once more

I stopped by a dealer on my way to work, to pick up some parts. Fuel line, new plugs, etc. This is generic fuel line, and not molded! If everything turns out right tomorrow, I'll have time to put it semi-back-together with new (not original) lines and see if there's any improvement. More parts to be cleaned but hey... I love the smell of de-greaser and fuel

Pics:

 

[adkranger]

Looking good! Make sure that fuel line makes a good seal to the tank.....could get messy otherwise.

 

[GeirA]

Carb rebuild needed

Cleaned and tested today, no luck. Fires with mix in carb, but no more. Looks like I have to rebuild this one as well.

Side note:
I went to my local dealer today, to get a quote on a kit for a Tillotson carb I have lying in wait. After some searching through various catalogues and such, they came up with this: 350-600 NOK (about $54.50 - $93.50) for ONE simple diaphragm kit, not even a rep-kit!!!

Lets just say I went home and ordered online from the US.
I'm now waiting for a diaphragm kit for my Tillotson AND for my Walbro. The price? $18 US, including 1st class international shipping!!!

PS! I live in Norway and yes, this is about right in general when talking prices on parts!!!

 

[fluffysaw]

You could buy a new carb for that.

 

[pioneerguy600]

Just in case someone reading this thread decides to try starting their saw by using a drill attached to the crank nut, the drill needs to be run in reverse if you are doing it from the flywheel side, it will work as I have done it many times.
Pioneerguy600

 

[blsnelling]

The fuel line they gave will likely not seal. You need that grommet to go into the tank. I recently bought a couple of those lines from my dealer.

I don't think new carbs are available for that model. No?

 

[GeirA]

I tried running the drill both ways, but it might have been lacking in power. Didn't have it charged at the time. Run it through the quick-charger when I get home and give it another go..

As I've been searching for parts for this carb (Walbro WA 86A) I haven't seen it adverticed, but I believe it was pretty popular so you might find it some place.

I'm actually enjoying the work on this thing even though it's a little tricky getting parts and stuff. As I've ordered the diaphragms etc I'll take the carb completely apart tonight and soak them in cleaner overnight. That should hopefully clear up any clogs and stuff.

PS! I removed one cover to get at the screen and WOW that thing was covered in goo. Completely! Guess if that was clogged, chances are the rest of it is as well..

 

[adkranger]

WOW! Those are crazy expensive prices on carb kits. :jawdrop: Must be they just want to sell you a new saw in Norway. I'd hate to price more rare parts.....

Yup, gummed up inlet screen = no go. Make sure to put on a fuel filter too.

 

[GeirA]

Waiting on the carb kits to arrive (takes about a week or so), I haven't had much to do. Some cleaning and some testing, but I still need some tools. I'm getting a compression tester and a few other bits and pieces to test more accurately.

One thing I figured I could do, was clean the carb completely getting it ready for the new gaskets and diaphragms. Set up a makeshift parts washer and also took the carb completely apart. The bigger and solid parts I threw in a jar and covered in cleaner, let them soak over 2 nights as they were rich with dirt.
Today I used a brush and compressed air and really gave it a good "grind". This uncovered some corrosion on the holder of the intake boot, but looks like there's nothing where it matters. Other than that I think it looks allright considering it's age. I've cleaned everything, and I do mean everything, with cleaner and brush. All passages and channels are clean and clear

Having nothing else to do right now, I've found a couple of questions:
1) Anyone have an idea on how I can test the impulse line without having the carb hooked up?
2) I can't for the life of me get a spark on this thing without having the recoil-/tank housing on! It sparks great when I reconnect the housing but not without it.. Probably just me thats a noob, but hey

Thought I'd snap a few more pics of the carb cleaned:
First is a pic I took before cleaning and disassembling

Rest is after cleaning:

 

[adkranger]

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....

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.

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..........

The impluse line: visually inspect first after cleaning off the oily buildup. Look for cracks, dry rot and permanent kinks. If it looks good, you could test with some LOW air pressure to check for leaks (say 10 psi or less). Vaccum would be a good test too if you've got some way to do that, to make sure it doesn't collapse at a weak spot. But in honesty you can usually identify these type of weak spots by feel with your fingers.