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Zanba RBK75 Carb Rebuild- On Echo Hedge Trimmer

Discussion in 'Mechanic and Repair' started by ed2hess, Aug 3, 2011.

  1. ed2hess

    ed2hess LawnSite Fanatic
    Messages: 14,452

    What is the procedure for getting the high needle to back out. Something stops it and I am afraid to force it. There is a brass collar where you stick the screw driver in that probably needs to come out. When you have the carb apart there is a plastic plug above it. The carb is bogging and I know it isn't getting enough gas with the needle full CCW.

    I have had the carb apart a couple times and cleaned up all the holes I could find. New kit is next but don't like not being able to clean that high needle chamber. Oh I put a new carb on off another unit and it works fine. I got two doing the same thing.
  2. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Messages: 2,249

    Is there a plastic limiter cap on the needle? If so, you will have to pull off the limiter cap in order to remove the needle.
  3. ed2hess

    ed2hess LawnSite Fanatic
    Messages: 14,452

    No....I will take a picture. There is brass collar that is apparently lightly pressed into casting of the carb. The collar has a hole big enough to get the adjusting scrwdriver thru it. I know that I have to take the collar out but I don't know if I have to take that plastic plug out. The plastic plug is perpendicular to the needle and when I removed it from my scrap carb I can now see the needle screw threads. I don't know if it somehow limits the screw from being backed out all the way or not. I am concerned that if I take that plug out then I will have either a air or fuel leak. The plug didn't just come out I had to drill it out entirely.
  4. sharkey

    sharkey LawnSite Member
    from Pa
    Messages: 50

    Can you post a pic of this carb that your working on?
  5. ed2hess

    ed2hess LawnSite Fanatic
    Messages: 14,452

    Kinda not very good at close ups...The largest hole is where there was a slug of plastic. I drilled it out. That hole goes down to the needle threads. When the needle is all the way CW there seems to be shank on the needle
    that may have hit the plastic. The second bad picture kinda shows the brass collar that is pressed into the alum casting and also keeps the needle from being taken out. I will try better pictures.


  6. MowerMedic77

    MowerMedic77 LawnSite Bronze Member
    Messages: 1,164

    Just keep backing the screw out, it will push the brass plug out of the carb body.
    I put the plug back in using a 4 mm allen screw the raised end of the plug fits into the spot
    Of the screw that you would normally put the allen wrench. Then just lightly tap it back into
    The carb body so it's flush like when you started.
    Posted via Mobile Device
  7. ed2hess

    ed2hess LawnSite Fanatic
    Messages: 14,452

    The plug would not pop out I drilled a small hole in it and then got a hook but no luck. I used a drill bit to grind it up....it is now a pile of dust. My question is...why does a plug need to be in that hole? Will the needle come out by just screwing the needle CCW forcing the collar out, leaving the plug in? This is a scrap carb I was just using to study the situation.
  8. dboyd351

    dboyd351 LawnSite Bronze Member
    Messages: 1,124

  9. ed2hess

    ed2hess LawnSite Fanatic
    Messages: 14,452

    Thanks I am making progress on the problem. That thread points out that I should have done a leak test on the carb. I don't know how to do that so well take it to dealer.
  10. ed2hess

    ed2hess LawnSite Fanatic
    Messages: 14,452

    Well I put a new carb kit in and I backed out that high needle and cleaned that jet hole. Put it back together and the results are the same. The unit bogs and fails to go to high speed. A second unit with same carb and same age ran fine after I got the plastic plugs out on both the high and low jet and adjusted them a small amount. So since I got a new unit with a new carb same model I am going to replace parts one by one until I find out what the problem is. I am coming to the conclusion that I don't think I will buy any more units with that zamba model carb.

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