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Want to buy Walbro HDB carburetor

Discussion in 'Chainsaw Parts' started by B.C., May 1, 2019.

  1. B.C.

    B.C. ArboristSite Operative

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    Looking for a new carburetor (or maybe one that definitely ran good on a saw without lots of smoke) for pro mac 610. I have two HDB, an l6 and l4. Neither run perfect, one I can tune real nice and it will idle great, and throttle up great, but it smokes like crazy.
     
  2. Duke Thieroff

    Duke Thieroff Fill your hands, you SOB!

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    Usually these model of saws smoking is a result of the impulse oiler diaphragm/gasket leaking bar oil into the crankcase and subsequently burning it.

    Your issue is likely related to that and not the carburetor itself.
     
  3. Hows57

    Hows57 ArboristSite Operative

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    I’ve got a 610 sitting on the shop floor in my way. You can have the whole saw for parts if you’re interested.
     
    Acornhill likes this.
  4. B.C.

    B.C. ArboristSite Operative

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    That would be real cool Hows57, I messaged you.

    Duke Thieroff - A few others have mentioned that as well now, and it makes sense. I'm not sure how to fix it though. I contacted Bob's in Ny who has a ton of old McCulloch parts and bought a brand new (newest it can be anyway, still like 20 years old or so I think, not exactly sure) and put that one before I fired it up. I don't actually remember if the old oiler smoked like crazy like that or not, I'd have to swap it on just to see. It would be a real shame if I couldn't get a good oiler working because I really like these saws. Not sure what to do to get it fixed up, this is the final piece.
     
  5. Hows57

    Hows57 ArboristSite Operative

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    I sent you a private message. You will see it in your IN box.
     
  6. Duke Thieroff

    Duke Thieroff Fill your hands, you SOB!

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    It's almost always the oiler diaphragm. Just replace that and you're good to go. They're still common to find and are super easy to swap.
     
  7. B.C.

    B.C. ArboristSite Operative

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    Well, actually, after a bit of testing just now I think that maybe I DO have a fuel problem after all. I ran it for only a few minutes, maybe 5 at most yesterday and I had filled the tank about 2/3 full. Figured I probably shouldn't need to but I checked the tank anyway before I started running some more tests today. To my surprise it was nearly empty.

    So I gassed it back up to about 2/3 full again, bout half way between 3/4 and 1/2 full (5/8 full I guess) and gave her a bit of run. I was mostly idling and then was throttling occasionally to see if I could clear the smoke. Oh btw I had drained the oil tank completely before starting today. Tried running for a while to see if the smoke would clear... It did not. After about 5 minutes or so I checked the tank and it was down quite a lot again about half way between 1/4 & 1/2 (3/8 full). That really seems like some insane fuel usage. So I'm pretty sure it's running SUPER rich at this point as that amount of fuel usage seems very, very high. (This makes sense too because the spray that comes out is more like gas than oil, it's not sticky like the bar oil is, it just wipes off like gas) It COULD also be burning bar oil but it seems pretty apparent it's DEFINITELY burning a crazy amount of fuel. I'm not sure how to fix that, it runs great and I have a new kit in it. The only thing I can think of to do is replace the little diaphragm check valve in there. I have a new kit in that carb, genuine walbro, and I have the lever set exactly at the height the walbro tool has on the side for hdb, which is flat/flush w/ the top, just a .005" below per manual spec. I did note in a manual I got from chainsawr that it mentions there is a governor that will make it run more rich if the rpms go too high. I don't know if that is what that little check valve diaphragm is for, and maybe it's not functioning is why it's running insanely rich. Only explanation I have other than just unknown/bad carburetor for whatever reason.
     

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