honda gx620 surging at WOT

Discussion in 'Mechanic and Repair' started by JRS Landscaping, Jan 28, 2014.

  1. cariboulou

    cariboulou LawnSite Member
    Posts: 160

    yes i believe that is it...it was in my case on a go cart I had to fix...
     
  2. Landrus2

    Landrus2 LawnSite Platinum Member
    Posts: 4,833

    Rob is trouble shooting this engine one of the best techs here on lawnsite
    This site is. Where we all can share info and who knows you could be right
    Just because we disagree don't make us right.:waving:
     
  3. JRS Landscaping

    JRS Landscaping LawnSite Senior Member
    Posts: 817

    restrorob... I removed the o ring like you said and re-seated it without it. It was originally seated all the way with the o ring on. so ruled that out. I'm really at a loss might just think its best to toss a new carb on it? I think some internal passage in the carb is gummed up? Are there any internal passages drilled in the carb body that can be clogged??
     
  4. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022

    There are internal passages, I don't know how you are cleaning but...... A can of Walmart "SuperTech" brand carb & choke cleaner with the little straw shot through ALL ports and passages watching for it to exit other ports/passages followed with compressed air should yield a clean open carb.....

    I say "SuperTech" because I KNOW it will cut varnish and dissolve gum unlike Gumout and some other brands that are nothing more than mineral spirits in a spray can (JUNK)......


    Short of buying a new carb, Since it idles fine I'd buy a set of JET DRILLS and drill the main one size larger and see how it does. I've had to do this on a few brand new Honda clone engines after a new carb didn't solve the high speed surge.....
     
  5. JRS Landscaping

    JRS Landscaping LawnSite Senior Member
    Posts: 817

    Funny you say that. I used gum out with compressed air. ill try again with the super tech.
     
  6. BigFish

    BigFish LawnSite Gold Member
    Posts: 3,366

    Are you sure the fuel solenoid is working ok? I'm not familiar with that particular carb, but I had a case where the nylon? tip that was molded/pressed on the sol. pintle was loose on the pintle. The unit ran fine at low-mid speed, but would act up intermittently at high speeds. I had cleaned the carb, etc. and checked the operation of the solenoid, pintle was free, no gunk buildup. The only way I discovered it was when I blew solvent/ air into the solenoid to clean around the pintle, I saw the tip move. It never came completely off, just moved up a bit. Apparently the fuel flow at speed was enough to dislodge the tip and restrict/ shut off the fuel!
    Anyways, check the solenoid and passages!
     
  7. Landrus2

    Landrus2 LawnSite Platinum Member
    Posts: 4,833

    If the carburetor still doesn't work correctly, you may have to take it to someone who has an "Ultra-sonic" cleaning machine. This machine uses carb cleaner and ultrasonic vibrations to get the very small passageways clean when traditional methods fail.:waving:
     
  8. BigFish

    BigFish LawnSite Gold Member
    Posts: 3,366

    I should add : You can usually hold the solenoid pintle in the retracted position by jamming a toothpick in it. Or remove the sol. and use a metric bolt to plug the carb.
     
  9. JRS Landscaping

    JRS Landscaping LawnSite Senior Member
    Posts: 817

  10. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022

    On some items Honda buys parts from two different vendors, That's why you will see two different parts/numbers for the same application. Either part will work, If you notice they appear to have dropped one vendor and both now have the same part number......
     

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