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Gx120 carb running choke only

Discussion in 'Mechanic and Repair' started by precision8m, Feb 24, 2013.

  1. precision8m

    precision8m LawnSite Senior Member
    Messages: 349

    I have a lesco core aerator with the 4 hp Honda gx120 and it will only run with full choke. I had a hard time getting it running in the first place. It would only run if you sprayed carb cleaner into the intake, so I took off the carb and cleaned it out. When I put it back on, it started right up with full choke, but if I moved it to half choke or open, it would die.

    Has anyone else had this problem or know what the solution might be. I don't think I have any air leaks as I have tightened the carb onto the engine pretty tightly.
  2. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Remove the float bowl screw, Under this screw is the main jet..... Remove it with a flat blade screwdriver and make sure the port is FULLY open.....
  3. precision8m

    precision8m LawnSite Senior Member
    Messages: 349

    I did this already. Carb spray flew through there pretty well.
  4. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    If the engine only runs on full choke there's a restriction in the main circuit of that carb, Try cleaning again.....
  5. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Messages: 2,249

    As Rob indicated, clear the main jet as he described. It the fuel nozzle didn't fall out when you removed the main jet, with the flat of a screwdriver reach into the venturi and push the fuel nozzle down and out of the barrel of the carb. If I remember semidecent, there are about 12 little ports in the fuel nozzle that become obstructed. Clear all ports and main jet, replace and give it another shot.
  6. piston slapper

    piston slapper LawnSite Platinum Member
    Messages: 4,335

    Its time to clean it again....
    This time...also remove the brass mixture tube..that is held in by the threaded jet..and clean it..
    Put a thin flat screwdriver into the carb throat and push down on it...should come right out..
    Something is still clogged..

    You beat me to the punch again...Dutch....
  7. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Messages: 2,249

    Trigger finger slow tonight, Slapper?
  8. precision8m

    precision8m LawnSite Senior Member
    Messages: 349

    I'll clean again. If that doesn't fix it, should I just replace with a carb from eBay?
  9. MR-G

    MR-G LawnSite Senior Member
    Messages: 479

    Once you get the tube out get a small wire (like a bread tie) use wire to poke thru all jets, mixture holes, ect. carb cleaner alone will not clear a bad glogg......good luck
  10. herler

    herler LawnSite Fanatic
    Messages: 5,139

    Stop playing around.

    First make sure, with the fuel line disconnected at the carburetor end, that fuel is coming through that end of the line.
    If it isn't, first check and see if there's a petcock or fuel shutoff somewhere in line.
    If it is, make sure the fuel flow is turned ON.

    If all that checks out and no fuel is coming through...
    Replace fuel lines and (if present) fuel filter.

    Then if fuel is getting TO the carburetor and it still doesn't run...
    Put a new carburetor on it.

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