Power problem with Kohler 18

Discussion in 'Mechanic and Repair' started by SamIV, Jan 1, 2003.

  1. SamIV

    SamIV LawnSite Senior Member
    Posts: 324

    I own an Exmark HP with an 18 hp Kohler. The problem is that it doen not always run at full power. Sometimes when I start it I will get full power but half the time I do not. This also affects the speed of the machine.
    I had the clutch replaced about 50 hours ago. This seemed to clear up the problem when I had it replaced it. The mechanic said he did nothing to the machine but change the clutch. Now the problem has returned. Doesn't matter if it's cold or hot. The choke is not engaged and the throttle is at full, and the air filter is clean. I'll start it at one property and I'll get full power. Stop the machine and go to the next property and will not get full power after starting it. Anyone have a clue.

    Thanks,
    Sam
     
  2. khouse

    khouse LawnSite Bronze Member
    Posts: 1,465

    check for water in the fuel tank
    check vent in the fuel cap
    change fuel filter
    check fuel pump volume
    rebuild carb

    i would do these things in that order
     
  3. muddstopper

    muddstopper LawnSite Silver Member
    Posts: 2,342

    First question, is this engine a two cylinder? I havent worked on kohler engines so I dont know, but if it is check the coil to see if it is cracked. I had one cracked on an Onan and it acted the smae way. It would crank and run but sometimes only one side was fireing and would result in extreme lose of power. In any case I would still check the fire on the plug and see if it was fireing properly along with a compression check along with the checks already stated by khouse, before I starting buying parts.
     
  4. SamIV

    SamIV LawnSite Senior Member
    Posts: 324

    Thanks for the quick replys. Yes it is a two cylinder. The power loss is not extreme so I will try to go through the first three suggeted by khouse first. Don't have a clue as how to check the fuel pump volume so I hope one of the first three is correct.
    Will get back with you.

    Thanks,
    Sam
     
  5. Fish

    Fish LawnSite Member
    Posts: 139

    These engines can run on one cylinder, whether bad compression
    or spark. Installing new plugs would be a good start. Is the
    engine a Magnum or Command?
    Fish
     
  6. SamIV

    SamIV LawnSite Senior Member
    Posts: 324

    The engine is a command. I replaced the fuel filter and cleaned the gas caps and it ran fine all day. Will replace the spark plugs also. Will let you know if this continues to work.

    Thanks for the great advice.
    Sam
     
  7. Mr.Wrench

    Mr.Wrench LawnSite Member
    from N.H.
    Posts: 65

    Sam, on your Kohler CV18 it is common for the #2 cylinder to foul a sparkplug very quickly because it is closer to the oil sump. Especially if your running your engine over filled on oil or your choke is not fully opened while running. And bouncing around on the trailer doesn't help either. Check the appearance of your sparkplugs. Your mechanic should have also done an ignition test on your engine to determine if the SAM module(Spark Advance Unit) is working properly. I've seen a lot of dead modules, or modules on their way out that will drag the rest of your ignition system down and cause a power loose. Also , how many hours are on your machine?
     
  8. SamIV

    SamIV LawnSite Senior Member
    Posts: 324

    Mr. Wrench, sorry about the late reply, had problems with my computer for a bout a week. My machine has close to 500 hours on it.

    Thanks
    Sam
     
  9. Joemow

    Joemow LawnSite Member
    Posts: 16

    Sam, I agree with Mr. Wrench about the igition module. I had problems with my 14hp command, & finally replaced the module. No problems since! I'll tell you though, I'll never buy another Kohler engine again! I run Ex-Mark HP with 21hp kawie, Scag w\b with 14hp kawie, & Bobcat w\b with 14hp kohler.
    In my opinion Kohler dosn't compare.
    Sounds to me Mr. Wrench really knows his stuff !
     
  10. Mr.Wrench

    Mr.Wrench LawnSite Member
    from N.H.
    Posts: 65

    Joemow, don't be so hard on Kohler, they are very good engines in their own right. We've had just as many ignition modules go on the Kawisaki V-twins this past summer. I swear that there must have been a run of bad modules on both manufactures engines. :rolleyes: Not to mention a ridiculous amount of lean conditions on the Kawisaki V-twin carbs!!!
     

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