23 HP KAW - CARB issue -on a deere 667 im out of ideas

Discussion in 'Mechanic and Repair' started by seabee24, May 6, 2010.

  1. seabee24

    seabee24 LawnSite Senior Member
    Messages: 619

    as stated 23 HP kaw , 1000 hours on it. i will get the model number in a min

    problem started a few weeks ago with a rough idle... it would run up and down. and to me sounded as if it was rich and bogging down

    So im mowing along 2 weeks ago , and it starts loosing power, almost as if someone slowly pulled the throthel back on me.

    then it dies. restarts with out too much problems and dies again...after 4 or five attemps it seems to be "acceptable enough to use the rest of the day.

    that week end i clean the carb. took most of it apart, took the bowl apart, and cleaned it. air line to blow out the jets. i found nothing inside of it. oil change , new filters, new plugs , new fuel filter. there is no screen in the tank to be clogged.

    put it back togther, ran "ok" good enough that i used it for the last 2 weeks with no problems.

    SO today same problem, it died on me. I noticed that if i pulled the choke it would run for 5-10 seconds longer with a smooth RPM sound, then it would die.

    It took extra cranking to get it restarted.

    now if you get it restarted and try to engauge the blades, it dies... only way to engauge the blades, is to pull the choke- even if the motor is warm.

    SO it idles rough, like its rich ...it runs full throttel, like its lean or at least has a fuel deivery problem. carb didnt appear to have an issues, altho i didnt tune it. and honestly i have no idea how you would on this carb.

    fuel pump seems to work and pump a good amount of fuel (judging by removing the "post pump fuel hose" while cranking

    so your thoughts?
  2. seabee24

    seabee24 LawnSite Senior Member
    Messages: 619

    KAW CODE FH680v-BS16
  3. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    When you took the carb apart did you remove the jets ?

    If so did you put each one back in the same port it came out of even though they looked identical ?

    Have you checked for proper spark at the plugs when it acts up or shuts down ?

    Has the valves been adjusted with-in this 1000 hrs. ?
  4. DT Lawn Care

    DT Lawn Care LawnSite Senior Member
    Messages: 850

    I'm leaning towards these last two suggestions. These Kaws require valve adjustment pretty often, recommended every 3-500 hours. Could be part of your deal. Could be a coil or coils, or the igniter. As Restro said, check your spark when it dies. Good Luck
  5. seabee24

    seabee24 LawnSite Senior Member
    Messages: 619

    no i did not remove the jets, everything was very clean looking to begin with , i figured the carb cleaner and a air gun would take care of anything left behind.

    Did not check for spark, but i cant imagine that is it...i will run a check , but it seems weird if it was a bad spark issue that messing with the choke would have any responce from the motor.

    no valve adjustment yet. what is the recommend proceedure and tollerance? i assume to check it at the rocker arms?
  6. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Yes it's weird, But adding more fuel (choking) to weak spark will cause a difference in engine running.

    Just to add;
    Even though the jets look the same they have different bore sizes, NEVER mix them up when removing for cleaning. Keep them separated so they go back into the same port they came out of....

    Valve adjustment procedure;

    Last edited: May 7, 2010
  7. seabee24

    seabee24 LawnSite Senior Member
    Messages: 619

    thank you very much super helpful.

    may i ask do you have the procedure on how to adjust the mixture for the main jets on the carb?

    or /and

    the exact carb cleaning procudre?

    looks like im going to have to get a book on this motor myself? is there a cd or downloadale repair manuel?

    going back to the weak spark issue, while pulling the choke the motor seems to run better - thus indicating a lean condition i belive
  8. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    There is no adjustments on the high speed circuit in this carb it's fixed jet, The low speed circuit is adjusted at the factory then plugged off per EPA regulations. So in essence this carb is non-adjustable....

    There really isn't a exact procedure for cleaning a carb, One just removes all jets possible then sprays carb & choke spray cleaner with the little straw (nearly any brand but Gumout) through ALL ports/passages and jets followed with compressed air.

    As for a manual, They are hard to find as a free on-line download. This is the cheapest hard copy I've found so far;


    As for the above, I don't disagree the least bit. But since you said you cleaned the carb and it ran ok for a bit I threw the weak spark out there as something else to check, Only because I've seen engines with weak spark/fouled plugs run better with a little choke.....
  9. seabee24

    seabee24 LawnSite Senior Member
    Messages: 619

    figures that EPA Carb crap-

    i moved that plate up just bit to increase the RPM , seemed to run better, still while at idle or full speed , it hunts , at least while its sitting still. once i kicked the blades on it smoothed out a bit.
  10. seabee24

    seabee24 LawnSite Senior Member
    Messages: 619

    well ran better, but still tried to die on me today , had to pull the choke to keep it running

    so i noticed while it was dieing, looking at the clear (new) filter up by the tank, it appears to me that the filter starts to run dry when it acts up? normally the filter is 80% filled with fuel. when it acts up, the filter has no fuel in it, ...shut the machine off, and the filter fills back up

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