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Walbro Carb

Discussion in 'Chainsaw' started by russellrewis, Dec 28, 2005.

  1. russellrewis

    russellrewis ArboristSite Lurker

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    Hello,
    Just registered and this is my first post, so excuse my ignorance. Came by this group by accident and glad I did. Very informative.
    Anyhow, I have a rebuild kit for a Walbro carb that I am about to use. I noticed it has a welch plug in it.
    What is underneath the welch plug that is in my carb and how do I remove/install it?
    My experience is that some things are better left alone.
    Will someone help me with this?

    Thanks,
    Newbie,
    Russell Rewis
     
  2. timberwolf

    timberwolf Addicted to ArboristSite

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    To remove, drill a small hole and pry it out with a small screw driver.

    I guess you could get a replacement, not sure if it is included with the carb kit.

    I have made them before, just make a hollow metal punch out of a scrap piece of metal tube, socket or whatever and punch one out from aluminum sheet, you do need to get the curved shape so it will expand when pressed into place.

    Just tap them into place with a small punch to install.

    Not sure why you need to remove the plug, only a couple of small passages below, unless it is gummed up or you know what you are modifying cant see too much need to go under there.
     
  3. skwerl

    skwerl Will Climb for food

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    In most cases the welsh plug should be left alone. How old is the carb and why are you rebuilding it?
     
  4. russellrewis

    russellrewis ArboristSite Lurker

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    The carbs (I have two from Pioneer p60s or 61s, not sure) are 25 years old but have only 90 hrs. running time. They have been sitting unused for 18 of those years. i am trying to get them up and going again so I purchased the kits from Rottmans and in the kits are these plugs. I would like to do a good job while I am doing this but I don't want to over do it.

    Russell
     
  5. Ax-man

    Ax-man Addicted to ArboristSite

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    They can leak, without an air pump it is hard to tell if they are leaking, as said best to leave it alone, if in doubt put a good fingernail polish over the plug, especially around the edges, and not too thick a light coat is enough, let dry, then reassemble the carb and hope for the best. Usually they are not a problem.

    Larry
     
  6. Gypo Logger

    Gypo Logger Timber Tramp

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    Hi Russell 99.99% of the time welch plugs should be left alone regardless of how may times the carb has been rebuilt. Since the advent of better filtering in fuel system, it's extremely rare to find obstructions within the body of the carb. That's been my finding anyway.
    John
     
  7. Simonizer

    Simonizer Addicted to ArboristSite

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    Remove it if the carb is contaminated with stale varnished fuel. A tiny sharp prick punch on a 45 degree angle can be gently hammered into the center of the plug. Be careful as they are only 63 thou thick and you can damage the tiny orifice(s) undernieth. Once you have a good indent, simply pry it out of position gently. Be careful not to damage the sealing area. When installing the new plug, use a flat taper punch gently and only in the center, straight down. When the convex part of the plug is flush with the carb body, stop. You are done.
     
  8. Ax-man

    Ax-man Addicted to ArboristSite

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    Molecule passed on a good way to remove and install those Welsh plugs. Use a small drill press to drill the hole to get the plug out, then put a punch in the chuck of the drill press with the machine off to press and seat the plug. I've tried it and it works slick and you can do a more precise job doing it this way.

    Larry
     
  9. Simonizer

    Simonizer Addicted to ArboristSite

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    This method has worked well for me hundreds, (literally) of times.
     
  10. Ax-man

    Ax-man Addicted to ArboristSite

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    Takes a gentle touch and practice like you said, Simon. Welsh plugs were never my favorite saw repair in the past, they still aren't :laugh: it is so easy to screw them up if aren't careful and have an eye for detail especially around the edges.

    Larry
     
  11. Fish

    Fish Account Hold

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    As said before, leave them alone, unless you have to. Generally, they usually cover the tiny orifices to the throat of the carb, which can be cleared
    most of the time from the carb throat side.
     
  12. russellrewis

    russellrewis ArboristSite Lurker

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    Welsh plug

    Thanks to everyone that took the time to reply to my post and offer such experienced information. It will be heeded.
    One more thing and I will stop. Varnish contamination was mentioned. I plan to soak the carbs but the owners manual says not to use carb cleaner but rather a good solvent. Why not carb cleaner and what is "good solvent"?

    Russell
     
  13. davefr

    davefr Addicted to ArboristSite

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    Scroll down to the ultrasonic cleaner thread. It seems like the best approach is a quick blast of carb cleaner and then soak them in something milder like varsol, mineral spirits, Coleman fuel, etc. (however I wouldn't use "crab dip" as bwalker suggests!!)

    Harbor Freight has an ultrasonic cleaner that goes on sale for about $25. It's just the right size for carbs.
     
  14. Stu in Tokyo

    Stu in Tokyo ArboristSite Operative

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    Don't know why they say not to use Carb Cleaner, but what I did on my old saw' s carb, and countless bike carbs, is to put the carb into a sonic cleaner.

    You can buy these fairly inexpensively, they are marketed as eyeglasses cleaners.

    Something like this....
    [​IMG]

    A buddy from the UK used to build Rally cars, and he said these thing work very well.

    I've used this type of thing on some carbs from a 1985 GSXR that had been sitting for 15 years, the carbs had a thick layer of varnish on them. I soaked them in Kerosene overnight and then put them into the sonic cleaner, warm water and some dish soap work well.

    This may help you out with getting he carb VERY clean, it worked on the old Husky I have, now I just need that carb kit for it....

    Cheers!
     
  15. davefr

    davefr Addicted to ArboristSite

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    It's because the carb cleaner's have a very low flash point and ultrasonic cleaning generates heat from the cleaning process. (even if the unit doesn't have an integrated heater). I'm sure all the vapors given off aren't too good for you either.

    I've always wondered what the best cleaning fluid to use. I've tried these formulas but haven't come to a conclusion as to what's best:

    Distilled water, ammonia and a little soap.

    Distilled water, 20% acetone, a few drops of Murphy's oil soap

    Kerosene

    I think I'll try some Coleman fuel next.
     
  16. Stu in Tokyo

    Stu in Tokyo ArboristSite Operative

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    Just to be clear, I DO NOT use carb cleaner in my sonic cleaner, I use warm water, and a little dish soap.

    Carb cleaner is expensive, and I find my water and soap in the sonic cleaner will out do the carb cleaner on it's own, plus the water and soap is no where near a toxic.

    Cheers!
     
  17. bugfart

    bugfart ArboristSite Operative

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    I like the Walbro carbs.
    For whatever reason, saws seem to kick out more power with them for me.
    Maybe it's that little hump on the top, who knows.
     
  18. russellrewis

    russellrewis ArboristSite Lurker

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    Carb Cleaner

    My wife is a jewelry freak but cleans it by hand. I can make points with her and get my carbs cleaned at the same time by buying her a sonic cleaner for a late Chirstmas present and "try it out" before I wrap it! This is good.

    Russell
     
  19. Stu in Tokyo

    Stu in Tokyo ArboristSite Operative

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    What I did was bring mine home, and then I helped my wife wash all of her Jewlery etc, and then I took it to the workshop :D

    Worked just fine!!
     
  20. rupedoggy

    rupedoggy Addicted to ArboristSite

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    Many of the small Chainsaw carburetors have a check ball in the high speed jet. It is made out of a plastic like material with a cover that looks like phenolic resin. It is my guess that soaking the carburetor in the strong cleaner, used commercially for automotive type carburetors, may dissolve this assembly. That is probably why it is not a good idea. Mike
     

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