Kohler Command ch25 running rich

Discussion in 'Mechanic and Repair' started by rockie, Oct 25, 2018.

  1. rockie

    rockie LawnSite Member
    Messages: 10

    I have a Kohler ch25s. This engine has 2400 hours. I feel great about it lasting this long practically problem free. My dad has been using this mower for the past several years on his property. Earlier this summer it bent a push rod on#2 exhaust valve. It sat summer before I had time to mess around with it. I replaced both valves (and lapped) went ahead and replaced the hydraulic lifters also new head gasket. Put new spark plugs in it and started it up. Now it is running rich both plugs are black soot and dry, while running a hint of black smoke is noticeable through exhaust. Smell is very rich. Put inline spark testers on both plugs. Both plugs have a steady bright light. I took off carb bought rebuild kit cleaned carb and still running rich. One thing I noticed while running I can push down the accelerator pump and it seems to smooth out not sure what that means if anything. I have done everything I know to do. Is my carb bad? I don’t mind replacing it just trying not to throw money at it with exhausting other options. What do you all think?
     
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  2. Walker56

    Walker56 LawnSite Silver Member
    Messages: 2,019

    Have you checked that your float level is correct? Did you verify that your float is not cracked or leaking? Double check that your needle is seating properly. Did you check that your bowl vent and or air bleed is clear? Here is a copy of the service manual. Fuel system starts on page 22.
    http://www.kohlerengines.com/engines/onlinecatalog/pdf/sm_24_690_06.pdf
     
    Last edited: Oct 25, 2018
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  3. rockie

    rockie LawnSite Member
    Messages: 10

    Thanks I will definitely look into that. I did shake the float and submerged it into water seemed to be solid. I’ll let you know what happens.
     
  4. Mownmachine144

    Mownmachine144 LawnSite Member
    Messages: 160

    I have a 2000 Honda rancher 350.
    Im having some of the same problems you are having. It runs rich in the winter for whatever reason.
    I lowered the idle on it, still rich.

    I think you need and i need a new carb.
    Hope you find the resolution for the problem.
     
  5. rockie

    rockie LawnSite Member
    Messages: 10

    Just know finding time to work on engine. Pulled carb cleaned again, this time I pulled the high speed needle and spring out and it was very dirty. Put back together, while trying to crank noticed exhaust gas coming out below the #1 cylinder muffler mount. Pulled head ordered new head gasket this one had torn. So now I’m waiting again.
     
  6. rockie

    rockie LawnSite Member
    Messages: 10

    Got the head gasket installed , motor put back together. It fired right up and same thing still running rich. I guess I need a new carb.
     
  7. properlandscaping

    properlandscaping LawnSite Member
    Messages: 120

    Needs more air. Any idea what model carb it is? Some can be adjusted.
     
  8. Mownmachine144

    Mownmachine144 LawnSite Member
    Messages: 160

    Make sure your carbs not made from Japan/china.
     
  9. rockie

    rockie LawnSite Member
    Messages: 10

    The carb is a Keihn 2485334s. Could the high speed adjustment needle be out? Even though it’s supposed to be fixed behind the cap?
     
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  10. properlandscaping

    properlandscaping LawnSite Member
    Messages: 120

    Yes, drill out the cap and give it a quarter turn. I had the same issue......starving for air. Both plugs were wet.
     
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