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Problems with Stihl 036 Pro, please help

Discussion in 'Chainsaw' started by Ryanw, Aug 21, 2002.

  1. Ryanw

    Ryanw ArboristSite Lurker

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    I am having problems with a Stihl 036 Pro. This saw is about 2 years old and has maybe 20 tanks of fuel through it.

    While cutting wood last week is suddenly would not start without having the choke on all the way. Once it fires I must get on the gas and feather it to get the RPM's up and keep them up to keep it running. If I let it idle it will cough, sputter then die. To restart it the choke must be turned on, pull the starter once and it will fire and die, open the choke, pull and it I can get it going by working the gas.

    This is what I have done: adjust and readjust the high and low needles to both side of what I consider the normal operating range for my location.

    Removed the carb and cleaned out the fuel pump and fuel strainer. It did have some sawdust in it. Initially I expected this to solve the problem but it did not.

    The fuel tank breather is clean.

    Air filter is clean.

    Spark plug looks good.

    I have removed the inlet needle from the bottom of the carb and cleaned that. It was a little dark but not what I consider dirty or worn. There was no annular groove on the end of the needle indicating wear.

    Removed the high, low, and idle screws and cleaned.

    Generally cleaned the carb.

    After reassembling everything the same problem described above continued.

    I pulled the carb off of a DIFFERENT 036 that is about 8 years old and installed that on the new Pro I am having trouble with. The troublesome Pro saw with the older carb ran flawlessley. This lead me to conclude that the problem is definately in the carb.

    I do not know what to do/check next. Any advice is greatly appreciated. Thank you, Ryan.
     
  2. Dennis

    Dennis Arboristsite MVP

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    Ryan, you may want to pick up a carb kit from your local dealer..although everything looks good...it may not be...did you remove the screen and welch plugs in the carb and clean as well..??the new kit should have new plugs...be careful when reseating them...make sure they seal...soak the carb in some cleaner and blow it out with air....just a couple things to try...
     
  3. Ryanw

    Ryanw ArboristSite Lurker

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    Thanks for the quick response.

    When you refer to the screen would that also be known as the sealing plate? If so I did not remove it as I didn't have a replacement handy. Or were you refering to the fuel strainer screen?

    I am not familar with a welch plug, is that also known as the the valve jet? A valve jet is the only thing I know of to seat in the carb. I did not remove the valve jet but did clean it as best I could.

    I have run Stihl saws for quite awhile and never had to put a carb kit in on such a new machine. This saw is very new and looks like it just came from the shop, that is why I am so stumped. Has anyone had a similar experience with a new saw?
     
  4. treeclimber165

    treeclimber165 Member A.K.A Skwerl

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    Virtually all carb problems stem from sloppiness (or just plain dumb luck) when fueling the saw or cleaning the air filter. The worst enemy of a carb is dirt, which can only get in from the fuel or air. If your fuel pickup filter was dirty after only 20 tanks of fuel, then I'd recommend being more attentive when fueling to not get crud in the tank. Same goes for when you clean your air filter. I tand to be a bit fanatical about cleaning the outside area before removing the gas cap or air filter, but I'm not the only one to fuel my saw so I still get crud in there from groundies 'helping me out'.
    Pulling off an air filter without cleaning around the outside first can result in large chunks of debris falling into the exposed venturi. This pretty much negates any benifit of using an air filter in the first place.
    I agree with Dennis, either install a rebuild kit in your carb or have a shop rebuild it for you. Cleanliness is of utmost importance in a carb rebuild, get help if you are unsure.
     
  5. jokers

    jokers Banned

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    Hey Ryan, the welch plugs are the little silver disks you see when you open up the carb. To really clean a carb you have to remove them and clean the orifices behind them ,then carefully, so you get a good seal, replace them with new ones. A small 1/4" drive socket will normally work to press them in. BTW, was the sawdust in the carb or the strainer? If it was in the carb you had better figure out how it got there or it will happen again. Russ
     
  6. Ryanw

    Ryanw ArboristSite Lurker

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    Thanks a lot guys!

    The sawdust was in the strainer, not the carb.

    Treeclimber, I totally agree with you on the cleanliness issue. So here is the whole story on the saw, it's not mine. My buddy left it at my place. I was serviceing my 029 but had not finished and I always like to have 2 saws with me so I grabbed my friends 036 Pro and my 036 for the day. As luck would have it the problem starts when it is in my hands so I'm left with solving the problem. I can't say exactly how it was treated/maintained/cleaned just know he hardly used it.

    Being a former USFS employee I have seen Stihls be seriousely abused and poorly or not maintained by inexperienced seasonal employees and continue to run, that is why they are all I own. Having seen the abuse they can take that is why I was surprised to find a problem I couldn't fix on such a new machine.

    I will clean and/or rebuild the carb and let you guys know how it goes. Thank you again for all the timely advice. On a positive note this problem led me to find this place, Ryan.
     
  7. sedanman

    sedanman Just cut the piano!!

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    Treeclimber165, I got into the habit of closing the choke anytime the air filter is in need of attention, keeps the chunks out. On my Jonsered 49SP there is an o-ring under the air filter cover (to retain the knob) which can split, the closed choke plate caught the broken o-ring once. BTW, the 49SP breathes from the bottom side of the air filter so theres no way to knock the big stuff off first.
     
  8. stihltech

    stihltech Addicted to ArboristSite

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    Make and model of carb, please.
     
  9. JimL

    JimL Addicted to ArboristSite

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    Yup what kinda carb ya got?
     
  10. treeclimber165

    treeclimber165 Member A.K.A Skwerl

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    Re: 036

    The Master has spoken.
    Gotta change your name to StihlGod. :D
     
  11. Ryanw

    Ryanw ArboristSite Lurker

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    It is a Zama Carb

    On the left (fuel intake) side this is printed on the carb body:
    S39B
    017A

    On the right side (adjustment screws) this is molded into the body:
    C3A

    Thanks for asking, let me know if I can provide and more info.

    Husky 288, I have already tried turning the L screw in to no avail. The symptoms are similar to running rich but adjusting the screws has not solved my problem.

    I am still not totally clear what the welch plugs are. Removing the bottom of the carb I see two brass colored, round plugs. One is refered to in my manual as a valve jet, the other is not addressed. There is also a nearly triangle shaped silver part with rounded corners identified as a "sealing plate." It is clear to me that if the sealing plate is removed it must be replaced but seems that the valve jet(s) could certainly be reused.

    It should be noted that I am using the manual for my 036 and I think it is a 034/036 manual but is not specific to the pro model that I am working on.

    Just love my old 036 I take care of it and it takes care of me, thanks again for the help.
     
  12. stihltech

    stihltech Addicted to ArboristSite

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    No, No, please leave me the way I am, I don't need Fish after me again.
    The sealing plate definitely has to come out. I use a fine wire to CAREFULLY clean the holes under it. As far as installing the new plate, I made a punch the same shape as the plate, works slick.
    The valve jet is best replaced also. Also probe the high and low jets to make sure they are clear.
    The inlet lever must spin freely on the axle. Soak the inlet needle in fresh clean fuel before installation. Has cured most problems on this carb.
     
  13. Dennis

    Dennis Arboristsite MVP

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    A shot in the dark here, and I know some of symptoms dont point toward this....but is there a possibility of an air leak..not allowing the saw to suck fuel on the low speed end...possibly in the fuel line itself....??? I dont know this particular saw...but have seen it before on others....
     
  14. WRW

    WRW Addicted to ArboristSite

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    Dennis,
    I've heard that before, just can't remember where. Something like "the bottom must be air tight before the carb will work right"
     
  15. stihltech

    stihltech Addicted to ArboristSite

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    Yes, the bottom must be air tight. But he has tried another carb and it solved the problem. An air leak would not be affected.
    UNLESS, the second carb had to be adjusted very rich to run correctly.
    Is this the case?
     
  16. Dennis

    Dennis Arboristsite MVP

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    Good call...forgot about the second carb....possibly the fuel inlet pipe on the carb is letting air by?? Seen those come loose before...????
     
  17. Ryanw

    Ryanw ArboristSite Lurker

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    The second carb did not have to be adjusted at all. Just bolted on and worked.

    OK I'm going to pull out the valve jets and sealing plate, clean the holes and replace the necessary parts. I'll be gone for a few days coming up but I'll let you know how things go. Hopefully I will have good news and won't need more advice on this carb.

    Thank you all again! Ryan.
     
  18. xander9727

    xander9727 The Silverback

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    Let us know.
     
  19. rahtreelimbs

    rahtreelimbs A.K.A Rotten Tree Limbs

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    Amoungst My Saws........Fool That Has Too Many!!!
    Why bring this up 2 yrs. later?
     
  20. xander9727

    xander9727 The Silverback

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    Two years is more than enough time to figure out a carb problem!

    On a more serious note: Sorry I didn't even notice. I got the email notification and I just responded. I thought this was part of the 361 thread.

    Give me a break........You know I'm not very smart........must you point it out to everyone.
     

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