My chainsaw "guilt project" is coming together

I picked up an old 042 Stihl at a yard sale a couple weeks ago and was going to just part it out and after half stripping it down, I got to thinking that it would be a shame not to make it run again.....Guilt set in, the needed parts were ordered and the clean-up began!

It's coming together nicely and I should be cutting wood with it tomorrow. The only concern I have is the Walbro WS-3 carb.....It has a separator plate with another gasket below the pump diaphragm and the one in the K10-WS kit doesn't look quite right.....we'll see how that plays out.

Glad you decided to get it going again, especially since the parts you do have look to be in really good condition.. The 042/048 models aren't really common. I've been keeping an eye open for a project one to add to my Stihl lineup, but the ones I've come across so far are in very good shape with a price to match.


Walbro carbs blö götz IMO. I hate rebuilding them.

Brmorgan said:

Glad you decided to get it going again, especially since the parts you do have look to be in really good condition.. The 042/048 models aren't really common. I've been keeping an eye open for a project one to add to my Stihl lineup, but the ones I've come across so far are in very good shape with a price to match.


Walbro carbs blö götz IMO. I hate rebuilding them.

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I've never had a problem with a Walbro............UNTIL NOW

Got the saw together and it fired right up, but was a bit lean when I hit the trigger.....Now after a few minutes the idle is hunting all over the place and it's dying after a few seconds over and over and it doesn't matter how much I richen the H or L it bogs off idle....GRRRRRRRR!!:censored:

I just took the carb apart for the 3rd time......I can't find anything wrong. I vac and pressure tested the saw after assembly and it's absolutely air tight, so I'm sure it's the carb.......One more try and I'm gonna give it a rest for the day!

Well, I have no explanation, but this last time I put the old metering diaphragm and inlet needle back in the carb at the same lever height and it runs like it should.....

Wood cutting video tomorrow maybe!

Metering lever height a little longer?
Pioneerguy600

Glad you saved it from the dead
and got it figured out. Good looking
saw. I have always liked the looks.



Lee

I rebuilt a Poulan 3400 this week and had the same issue with it. Replaced diaphrams and gaskets on the carb and it wouldn't settle down. Pressure tested the saw and carb, everything perfect. After pulling the carb out, checked metering lever and still the same issue. I put a the old diaphram back in and the stupid thing runs like a champ. So, what is lever not set right?

jockeydeuce said:

Well, I have no explanation, but this last time I put the old metering diaphragm and inlet needle back in the carb at the same lever height and it runs like it should.....

Wood cutting video tomorrow maybe!

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Dang fine looker! Props to you for putting her back in the wood.

That's a fine looking saw.

I will be listing a TON of 042/048 stuff in the near future in my Ebay Store. Just thought that I would give you a heads up if you need spares (mint plastics, motor stuff, etc.).
And BTW, very nice looking saw, I am kind of curious as to why they didnt get more attention than what they did. Definitely a leap for Stihl at the time in the cosmetic department!

Well I took the old girl home and gave it a test run, but it still isn't quite right.....It just idles and revs a bit too inconsistently. After a few cuts it's coming out of the cut a little lean and takes a bit to settle back down, no matter how I adjust the carb........It vac tests good, new fuel line and filter, and the tank vent is fine, so that pretty much leaves the carb.

I'll mess with this carb a bit more and maybe try raising the inlet lever height a bit???? I had an 028 act just like this and I finally just changed the carb to make the problem go away.

I'm in too far to give up now.....Thanks for the suggestions and props!

procarbine2k1 said:

I will be listing a TON of 042/048 stuff in the near future in my Ebay Store. Just thought that I would give you a heads up if you need spares (mint plastics, motor stuff, etc.).
And BTW, very nice looking saw, I am kind of curious as to why they didnt get more attention than what they did. Definitely a leap for Stihl at the time in the cosmetic department!

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You never know, I might need a carb!!

Is that one of the Walbros with the little non-serviceable check valve inside? If it's stuck open, maybe it could be running a bit fat no matter what you do? I don't know much about the subject, just seen a few others here griping about difficulties with them from time to time. Most of the time if I can't get a saw to come back down to idle acceptably but it tests fine for leaks, something's causing the carb to inexplicably mix too rich, which in turn causes me to turn the idle adjust in farther than it should be, which gives the saw more air than it needs to idle...

I've also had other saws where the margin for error for tuning the carb was almost nil, like 1/64 turn; I don't know what causes that, maybe damaged needle seats from over-torquing them or something.

Brmorgan said:

Is that one of the Walbros with the little non-serviceable check valve inside? If it's stuck open it could be running a bit fat no matter what. Most of the time if I can't get a saw to come back down to idle acceptably but it tests fine for leaks, something's causing the carb to inexplicably mix too rich, which in turn causes me to turn the idle adjust in farther than it should be, which gives the saw more air than it needs to idle...

I've also had other saws where the margin for error for tuning the carb was almost nil, like 1/32 turn; I don't know what causes that, maybe damaged needle seats from over-torquing them or something.

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I'm quite sure it's coming out of the cut lean not fat......I'm always seeing new things, but this thing has an extra plate that the pump side seals against with another gasket under it......I'm still questioning if the right gasket is in the kit for under that plate.....The only gasket that would work was slightly different than the original.......I'll play with it some more....Thanks for your thoughts, Brad.... It'll idle like a champ all day long until you start making some cuts then it's all over the place.

jockeydeuce said:

I'm quite sure it's coming out of the cut lean not fat......I'm always seeing new things, but this thing has an extra plate that the pump side seals against with another gasket under it......I'm still questioning if the right gasket is in the kit for under that plate.....The only gasket that would work was slightly different than the original.......I'll play with it some more....Thanks for your thoughts, Brad.... It'll idle like a champ all day long until you start making some cuts then it's all over the place.

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OK... Well, possibly yes and no on the lean thing. If the idle screw is in too far because of a rich mix, the saw will continue to get too much air after the trigger is released, which in effect does cause a lean mixture and not allow the RPMs to drop off properly. I don't want to come across as disagreeing or anything since I'd have to see/hear it running to really give an honest opinion, just saying that it's one of those symptoms that can throw you off because it seems like the cause should be the opposite of what it really is.

Take, for example, my ported 181SE. It was the first saw I ever did cylinder work on, so I didn't have an ear for tuning such saws yet. Rather than blow it up I erred WAY over on the side of caution and it ended up quite rich for a long time. It had torque to no end, but I was always fighting with idle issues. Take a look at the end of the first video I made with it, early summer last year:

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Notice how it continued to run on quite badly there. At first I thought it was partly just a weak clutch, so I changed that out. Same thing. Later last year I was brave enough to lean it out a fair bit on the high end, and quite a bit on the low too - just to where it'll still keep a nice snappy throttle response but no more. Now it hops right down to idle in just a couple seconds:

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So I dunno. I'm always interested when carb/tuning issues are concerned because that's where I think I have the most to learn still. I'll be keeping an eye to see what the culprit in your case turns out to be. I just fixed another 181SE for a fella that needed a carb rebuild, and the new metering lever would NOT do the job right out of the bag; I had to bend it a fair bit to keep it from flooding the engine. But, that was a NAPA rebuild kit (all my dealer carries for older Tillies now), not an OEM Tillotson. So who knows. I'm telling you though, those Walbros are bad news and will waste a lot of your time! There always seem to be enough leftover parts in a rebuild kit to build like three different carbs, and of course not always identical to what you have on-hand and no documentation to help a guy out.

I see what you're saying Brad, but I'm about 1 turn out on the L, so I don't think I'm compensating for a rich condition and it'll idle like that beautifully in any position........I noticed it's hard starting cold too and likes lots of choke, so I think it's a lack of gas.

Here you can watch it after the cuts......It's running on really bad and got the lean "wah wah's", but once it settles down it'll go back to that perfect consistent idle again in a few seconds and the lean bog "almost" goes completely away......One way or another I'll get it!!

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Nice old saw, great job. I have one of those somewhere for parts, it got clobbered by a tree.

daddy66 said:

Nice old saw, great job. I have one of those somewhere for parts, it got clobbered by a tree.

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We might have to talk about a carb...

Wouldn't be a very long conversation......if I can find it, it's yours.
What model number is it?

Never mind, I went back and read it again.......( I can read....really)

WS3, let me look.

daddy66 said:

Wouldn't be a very long conversation......if I can find it, it's yours.
What model number is it?

Never mind, I went back and read it again.......( I can read....really)

WS3, let me look.

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That's very generous.....I sent you a PM as well, but I would prefer to find a WS-25.

Ya it does sound a bit lean - if you have the low needle out 1 full turn and the idle screw completely backed off and it's still revving that high, there's air entering the system somewhere. I'd check the impulse, myself, if it's also a pain to start, or just keep rebuilding that carb with every gasket and diaphragm combination possible. You never know.