Kohler Command Pro 18hp Leaving Me Stumped

Discussion in 'Mechanic and Repair' started by clean_cut, Sep 11, 2011.

  1. clean_cut

    clean_cut LawnSite Bronze Member
    Messages: 1,327

    I've got a command pro 18hp on a scag walk behind that's been working well for a few years, a while back it started to run rich, and then not at all, due to the plug being fowled so quickly. After cleaning the plug the mower runs alright for a few minutes until the plug gets fowled again and it begins to misfire and eventually quit running, here's what I've tried to fix it....

    Checked airflow to carb
    Replaced fuel filter
    Switched spark plugs
    Re-gapped spark plug (.020 in.)
    Cleaned carb. MANY times
    Installed a carb. kit that included a few gaskets, fuel inlet seat, and fuel inlet needle
    Adjusted carb. (even at the leanest setting it still runs very rich)
    Checked that the carb. float does float and isn't broken

    It's been sitting in the garage for about 1/2 a year now, I just can't figure out what's wrong with it, do I need a whole new carb ($130-150ish)?

    The carbon on the plug seems to be a dry powdery carbon, not oily.

    The exhaust also seems strange, it has a chemical smell/fume to it, that seems to burn your nose, maybe the engine's always ran like that though.

    Anybody got any ideas on what the issue could be or how to fix it?
  2. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    There's a right way and a wrong way to install the seat, Which way did you install ?

    I see no mention of cleaning the fuel tank ?
  3. clean_cut

    clean_cut LawnSite Bronze Member
    Messages: 1,327

    Well to install the seat, I got out a hammer... just kidding, I used the tool given in the kit to get it seated at the right height, following the given instructions, so it should be installed correctly.

    I never cleaned the fuel tank, but I have drained it and put fresh gas in there, I forgot to mention that.
  4. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Tool in the kit ? Was this a "Kohler" kit ?

    Just need to verify you got the seat in properly.....

  5. clean_cut

    clean_cut LawnSite Bronze Member
    Messages: 1,327

  6. piston slapper

    piston slapper LawnSite Platinum Member
    Messages: 4,337

    Is the Command a single or twin cylinder? (Need model and spec#)
    Havent seen any command twins with serviceable seats. Whats up with the .020 sparkplug gap?
  7. clean_cut

    clean_cut LawnSite Bronze Member
    Messages: 1,327

    The engine is a single cylinder model # cv493t and spec # 27513, yeah, I just checked the manual and it states states that the spark plug should have a .030 in. gap... oops, I guess I just had .020 stuck in my head for some reason and didn't even think to check the manual when I adjusted it. The spark plug gap might be part of the problem but I still can't figure out why it's running so rich.

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