Kohler CV14S problem !!!!complicated!!!!

Discussion in 'Mechanic and Repair' started by mrracer98, May 24, 2009.

  1. mrracer98

    mrracer98 LawnSite Member
    from USA
    Messages: 5

    Hey all, new to the forum, looking for advise... I am a trained Small engine Mech, though I never worked on the field, just spin wrenches for fun. So I am out of practice a bit...

    Question, I am working on a friends Dixon ZTR with a kohler CV14S in it. The problem is this... It Runs GREAT, mows GREAT... though seems once under load and warm, it will just die out. Seems like a fuel delivery problem, as, you can keep it running for a short time longer when it starts, if you put it to full choke. Then after about 5 more seconds, it just dies all together. The warmer it is, the more often it does it.

    Here is what it is NOT: It is NOT carb (has been cleaned and rebuilt, I found a spot for a welch plug that was not installed, but you know how carb kits are (for several models) so I left it out as I found it.... It is not a fuel cap/venting issues. Has a new fuel filter, the in tank filter is fine and cleaned. The fuel pump is clean and in great shape, seems to work well.

    I am thinking possibly a seal/gasket somewhere that is getting warm, expanding causing a lean condition? Or some sort of electrical condition that once warm, and resistance goes up is causing problems... any help is greatly appreciated... Thanks!
  2. ricky86

    ricky86 LawnSite Silver Member
    Messages: 2,139

    That welch plug wasn't missing. They don't use one. Hook an aux fuel tank to the carb to isolate fuel supply from engine. See if that helps. I don't agree with you gkt expansion theory. And you don't know, at this point, if it's the carb or not.
  3. mrracer98

    mrracer98 LawnSite Member
    from USA
    Messages: 5

    Only problem with that is I need it running, working (mowing) for about 5-10 minutes before it does it... however when it does do it, if I quick take off the fuel cap, it changes nothing.... ALSO I have completely occluded the cas cap (i.e. covered with rubber so it was air tight) and it still did it no change... I also had the tank completely apart, and the micro screen on the petcock was cleaned and functional...

    and FYI: it started last year, and has slowly gotten worse.. i.e. first it would run 30 mins, then do it, then 15, now like 5-10 minutes and it does it... also runs shorter and shorter after each time it is restarted.

    You still think it is fuel delivery?

    NIXRAY LawnSite Senior Member
    Messages: 520

    Could be considerd a stupid question BUT assuming this is an air cooled unit are the 'fins' clean and free of blockage? perhaps its not getting proper cooling and shuting down?

    What does the spark Plug look like? (are you sure its the correct heat range?)

  5. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Sure sounds like it.

    Are YOU the one that rebuilt this carb ?

    Is there any fuel in the float bowl the second it shuts down ?

    How long doe's it need to sit before it will re-start ?

    I see no mention of spark testing during operation (in-line tester) or seconds after shut down ?

    As the sticky thread above this section states, Posting model and spec numbers are always helpful ?
  6. mrracer98

    mrracer98 LawnSite Member
    from USA
    Messages: 5

    OK... Yes I am the one that rebuilt the carb... the carb seems to be functioning flawlessly. It will start nearly right away after it dies... i.e. 5-15 seconds. But as stated earlier, it will run shorter and shorter amt of time after the initial quitting.

    spark, I am trying to get a hold of a spark board, as I seems to have lost mine, my friend has one, however when looking at the spark right now (on the plug) it is part blue, part orange, so perhaps a weak spark has something to do with it also.

    Model: CV14S
    Spec: 1428
    Serial: 2319416454

    It is a dixson ZTR 4422 it is a walbro carb
    Spark plug in it is a Champ RC12YC and on the darker side of chocolate brown and nice and dry.
  7. mrracer98

    mrracer98 LawnSite Member
    from USA
    Messages: 5

    I will check the float bowl after shut down... and do you know the specs for the coil to flywheel clearance?
  8. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Ignition module air gap 0.008-0.012" (0.010")

    I just worked on a Kawi yesterday morning that had the same symptoms as this Kohler, Someone else had cleaned the carb but a quick listen sent me to the carb.

    I found the problem by checking the fuel level in the bowl at shut-down.

    The tip of the low speed idle jet plugged solid, The fuel inlet is larger than the hole for the float needle valve tip and this inlet was plugged nearly closed with rusty trash. Left sitting a few seconds the pump pressure would fill the bowl enough for restart but it would shortly die because there was not enough fuel entering for it to continue running.

    A GOOD carb cleaning along with the fuel tank and new filter sent this unit home and made my pocket a little fatter.
  9. mrracer98

    mrracer98 LawnSite Member
    from USA
    Messages: 5

    Well... I had taken the carb off myself and cleaned it... and believe you me it was CLEAN!!! I usually work and tune motorcycles and snowmobiles... carbs far more complicated than this kohlers... EVERYTHING was taken off that could be, and that was serviceable (less the throttle plate etc). I changed ALL fuel line, flushed the steel line, put all set screws to default factory settings, took the tank, and petcock apart flushed and cleaned both, and everything was high pressure cleaned with air compressor as well...

    HOWEVER, the coil gap was only about 0.002" and rusty, I cleaned off the rust on the coil and the flywheel that gave me about 0.0035-0.004" gap... Seems to work better now. I cannot get it to repeat it after that. I know a hot coil gives more impeadence, so perhaps this was the reasoning behind it all? I am not sure it is kind of frusterating, but I am thinking this fixed it.

    I checked compression... 188 PSI. lol so that is fine.
  10. laboredm

    laboredm LawnSite Member
    Messages: 2

    I have the same problem with my Kohler. I have tested all and I know that there is no spark is my problem. I have an inline spark tester and I have good spark when the engine is cold, I got the engine to run for 1/2 hour and ran out of gas. Filled the tank and now hot there is no spark. cleaned everything. What would cause there to be no spark when hot??????

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