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honda gx620 surging at WOT

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

  1. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    OK..... Since you've been into the carb a few times now, I have a few more questions;

    1) Are you test running with the air filter in place ?

    2) There's a small spring over the throttle link rod that hooks to the carb throttle shaft and governor arm, Is this spring hooked up and not stretched ?

    3) This "surge", Is it a slow surge or a (for lack of a better word) pecking surge (abrupt) ?

    4) Do you have a tach to check high speed RPM's ?

    We're eventually gonna get to the nitty gritty of this thing......
  2. JRS Landscaping

    JRS Landscaping LawnSite Senior Member
    Messages: 817

    1 yes with air filter and housing. No pre filter tho.
    2 spring is in place. How do i test if its stretched? All the spring coils are tight. There are 2 holes on the plastic lever where it connects to the carb. One for spring and one for throttle linkage. both are about the same size Could it be reversed? are they supposed to be in the same hole? I took it apart and put it back together as i found it. ( it did the same surge before i took the carb apart)
    3 Surge is on the slower side and rhythmic Not a real choppy.
    4 Tach no but it sounds like its running pretty close to normal RPM
  3. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    With everything you've done and checked, There's only one thing left if slightly applying the choke smooths it out.

    There's two different size main jets for this carb, #92 high altitude (smaller) and #95 standard (larger)..... If you have a #92 in it now, That could be the issue. Buying a new carb at nearly 200 bux may or may not solve your issue because most don't denote main jet size.

    You'll need to tear the carb back down again and see which # size jet is in it, Most are stamped in the face area..... If it is the #92 buy the #95 and see how that does, If it already has the #95 jet let me know.....
  4. JRS Landscaping

    JRS Landscaping LawnSite Senior Member
    Messages: 817

    the choke has to be open a little more than slightly. Its more like 1/4-1/3 choke. I have a 95 main and the skinny long one (pilot maybe?) is a 55c. #13 in link it has the rubber o ring on it that goes up into the carb throat. Only thing i noticed is that has a few holes in in and when installed #14 in the link slides over the holes in the carb throat. Is that part #13 supposed to be seated all the way in the carb throat to the flange? (not the middle one just the top one under the rubber o ring. I can't seem to get it to the flange and don't recall how it was. It is maybe 1/8" from flange?

    Link http://www.partstree.com/parts/?lc=...N,+VIN#+GCARK-1000001&dn=2410Z6C6EZ6C0E1400CI
  5. JRS Landscaping

    JRS Landscaping LawnSite Senior Member
    Messages: 817

    Just tried seating #13 and i couldn't get any more out of it. Is there a possibility that an internal circuit is clogged? Also would it hurt it running it like this as i need use it to weld something real quick
  6. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Run it as is..... I'll get back later.
  7. JRS Landscaping

    JRS Landscaping LawnSite Senior Member
    Messages: 817

    Alright thank you! for all your help so far i really appreciate it. If you are close I'll pay you to look at it/ fix it.
  8. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Carefully remove the o-ring from #13 and see if it seats all the way in, If so replace the o-ring and wipe a little oil on it then try seating again.

    Ethanol tends to cause o-rings and rubber bowl seals to swell soon as air hits them thus making it impossible to reuse them......
  9. cariboulou

    cariboulou LawnSite Member
    Messages: 160

    isnt there a govenor inside the crankcase?? I had this issues with a smaller older honda and the plastic govenor had broken off inside crankcase!
  10. Landrus2

    Landrus2 LawnSite Fanatic
    Messages: 5,006

    Hey cariboulou do you mean this gear.
    Usually when these go you will notice engine out of control.
    In this case we can rule this out in my opinion:waving:


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