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Help with 041 carb

Discussion in 'Chainsaw' started by Haywire Haywood, Mar 8, 2008.

  1. Haywire Haywood

    Haywire Haywood Fiscal Conservative Social Retard

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    Couple of quotes from other threads for a bit of background.

    Well, carb problems have come to pass it would appear. I did a search and Lake said that spitback was sometimes due to worn piston skirts... this is a NOS piston and cylinder so that rules that out. I checked the metering lever this morning and it's level as a diagram I found on a search showed. I fished the rubber tipped metering needle out of the trash and will put that back in later today to see if that cures an unknown needle-seat seal problem.

    Is there anything else I should look at while I'm in there?

    thanks,
    Ian
     
  2. West Texas

    West Texas AboristSite Guru

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    I've never had this problem on a saw; but, when its on a car, it usually means the timing is off. Has a mod been done to any of the ports?

    My smaller Walbro carbs all have rubber tipped needles. Every now and then, one of these tips gets worn and needs to be replaced. I'd give the rubber tipped needle an eye ball inspection and if it looks OK, put it back in the carb.
     
  3. Haywire Haywood

    Haywire Haywood Fiscal Conservative Social Retard

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    No mod as such, but the base gasket was NLA so I made a new gasket that is about 005 thinner before installation which would change the port timing a touch. Don't know if that would cause what I'm seeing. It starts fine, idles fine, revs to spec but has no power in the mill. 150lbs of compression, 2 tanks of gas through it since reassembly.

    Ian
     
  4. Scooterbum

    Scooterbum Addicted to ArboristSite

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    How does it respond to the hi side adjust?Does it richen right up when you crank it open(forget the tach for this and use your ears for the burble)? Base gasket a little thinner should'nt be an issue.Ignition electronic or points?
     
  5. Haywire Haywood

    Haywire Haywood Fiscal Conservative Social Retard

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    I'm quite deaf to burble. Try as I might, "burble" doesn't mean anything to my ears. I'm quite useless without a tach and only marginally useful with one. I've not had the flywheel off so I don't know if it's points or electronic.. how do I tell?

    Ian
     
  6. Scooterbum

    Scooterbum Addicted to ArboristSite

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    A search for "041 ignition" will bring a wealth of knowledge.(not being smart or anything).

    Where is your high side set at?
    If you can't hear the difference,try it at 1 1/4,1 1/2, and 1 3/4 and see if you see a difference in torque in the cut.

    What I gather from your posts is that it is falling in the cut like no power,is that correct?
     
  7. Scooterbum

    Scooterbum Addicted to ArboristSite

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    Shame your not closer,I'd say bring it over and we could put it in some wood and figure it out.
     
  8. Haywire Haywood

    Haywire Haywood Fiscal Conservative Social Retard

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    Looks like electronic ignition. No adjustment holes in the flywheel.

    As far as where the H was, I pulled the needles this morning to see if they were dirty and to give it a good squirt of cleaner down the holes to try to flush them and was startled to find it was under 1 turn out to achieve 9800 WOT rpm. I put it back in at 1 turn out, cranked it and it was way rich, by that I mean low RPM.

    I failed to mention that it was running hot before which would indicate to me a lean condition and the needle position kinda backs that up. Why it wouldn't rev without leaning it excessively and at the same time spit back so much is a mystery.

    Ian
     
  9. Frank Boyer

    Frank Boyer Addicted to ArboristSite

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    Changr the fuel and impulse lines. Then readjust the carb. My 041 needed them every few years.
     
  10. Haywire Haywood

    Haywire Haywood Fiscal Conservative Social Retard

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    Both hoses at the carb are new. Didn't change the pickup hose. Will look and see what kind of shape it's in, but I did change the fuel filter and I seem to recall it's good.

    Ian
     
  11. Haywire Haywood

    Haywire Haywood Fiscal Conservative Social Retard

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    I went back through the carb today. Completely disassembled it short of taking the welch plugs out and blew carb cleaner through all the passages. All clear. Set both needles to 1 turn out and it ran badly at about 8k and smoked like a mosquito fogger. Just for kicks I pulled the fuel pickup to check condition and it's a little soft but fine, no cracks or deterioration.

    Any suggestions? It ran fine before I changed the cylinder to the super version.

    Ian
     
  12. Fish

    Fish Account Hold

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    Look at the ignition closer.
     
  13. Haywire Haywood

    Haywire Haywood Fiscal Conservative Social Retard

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    Ok, will borrow a flywheel puller from somewhere and see what there is to see under there.

    Ian
     
  14. Fish

    Fish Account Hold

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    Where you at in Ky?????
     
  15. Haywire Haywood

    Haywire Haywood Fiscal Conservative Social Retard

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    Richmond, about 30 min south of Lexington.

    Ian
     
  16. andrethegiant70

    andrethegiant70 Addicted to ArboristSite

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    Hi, Ian, I suspect you've read what I have about the seal between the oil tank and the crankcase.....I would maybe dump most/all the oil out of the tank to make sure you're not getting oil into your crankcase...the "mosquito fogger" comment is of concern. Maybe just make sure you don't have TWO things going on at once.
     
  17. Haywire Haywood

    Haywire Haywood Fiscal Conservative Social Retard

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    What is getting me is that none of this was disturbed during the change and wasn't an issue before. Four Paws said that there were several timing changes throughout the 041 line. Could it be that i need to re-time the ignition?

    Ian

    Maybe the mosquito fogger comment was a bit much. It smokes like it's running way rich and at 2k under spec at just 1 turn out on the H. I've had oil in the cylinder before and it doesn't smoke like that.
     
    Last edited: Mar 10, 2008
  18. andrethegiant70

    andrethegiant70 Addicted to ArboristSite

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    It seems that I remember that thread. Carb issues can sure be tough.... I recently rebuilt a Dolmar 110 carb like 5 times trying to figure out what was wrong with it, did the same thing you're doing, fooled with the inlet needle height, cleaned under and replaced the welsh plugs, the works.....everything on the saw told me it should run like a banshee. I finally shelved the thing 'till I found a replacement WT-76 carburetor (six months it took), rebuilt THAT one and the saw runs like new. Most of the time these carbs are esy to work with, other times they can be full of bad voodoo. I will say that its easy to understand why a carb may run lean, not so easy to diagnose a chronic rich condition.

    Unfortunately, you need a real carb tech on this one or you need to swap out the parts for diagnostic purposes. I took door number two.

    Oh, as a P.S., my philoosophy is generally that when a saw is working, then I work on it, and then the saw DOESN'T work anymore, I'm usually the culprit.... again, I suspect you've thought of this, but go make sure you've got the right diaphrams in the right place, and hit all the passages with carb cleaner (again).....remove and check the needle seats for contamination and deformation. Its certainly possible that you've dislodged some crud that has made its way to the next constriction.
     
    Last edited: Mar 10, 2008
  19. Haywire Haywood

    Haywire Haywood Fiscal Conservative Social Retard

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    Hmmmm... I do know where another 041 carb is that I might be able to put on there.... don't I Dustytools.... MUAHAHAHAHA...

    I need to go through all that info on 041 ignitions that Andy posted awhile back. Maybe I'll learn something there. Maybe not. I've had it downloaded for about a week now but haven't gone through it yet.

    Ian
     
  20. Lakeside53

    Lakeside53 Stihl Wrenching

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    What Andre said... Read up (AS search) on the oil pump leak issues...
     

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