Scag 36" belt with Kw 12.5 hp

Discussion in 'Mechanic and Repair' started by CTservices, Jun 29, 2003.

  1. CTservices

    CTservices LawnSite Member
    Posts: 103

    Got a problem with my belt drive scag wb. Engine seems to be missing at full throttle, blades engaged. When it happens, sounds like a spark ping. I've changed the plug per the Kawasaki manual, changed air filter and pre filter. Doesn't happen all the time. Fuel filter has maybe 30 hrs on it. Engine runs fine on start up, problem seems to happen after it warms up, and hits deep grass a few times. I would appreciate your guys help, don't have the $ to take to the dealer right now.

    Thanks
    Chris
     
  2. Rustic Goat

    Rustic Goat LawnSite Bronze Member
    Posts: 1,194

    You using an NGK plug, if not do that for starters.
    Check all cabling, nuts, bolts, air filter, and especially the choke/throttle cable and its settings.

    Is this an older unit?
     
  3. CTservices

    CTservices LawnSite Member
    Posts: 103

    I was told it should be about 4-5 years old. I haven't ran the numbers on it to get a exact date. I am the second owner. It has a new champion plug. Haven't had any problems with champions in all my other equipment. All cables appear tight and linkage good. I don't know if I just need to clean/rebuild the carb, or if it could be a coil/ignition module intermittent failure. I'm just trying to save a diagnostic fee at the local small engine mechanic.


    Chris
     
  4. Rustic Goat

    Rustic Goat LawnSite Bronze Member
    Posts: 1,194

    It's all guess work till a diagnostic is done, time vs money for a reality check.
     
  5. xpnd

    xpnd LawnSite Senior Member
    Posts: 378

    How many hours in those 4-5 years from the first owner? If you determine the engine is worn (low compression) do not simply replace with the same 12.5 Kaw. They are pitifully undersized for this mower. If money is an issue compare the cost of a short block and that of a new engine 14hp or above. this year I set an 18 hp Kohler on my 36 and am absoultely thrilled with it .
     
  6. CTservices

    CTservices LawnSite Member
    Posts: 103

    Could you provide me with some part numbers for the 18hp kohler and the other engines you may have consdiered? My 12.5 is shot, valve seat has rode out of the block. How hard is the 18 to pull start? Due to cost, I may have to go with a 14hp, but I would appreciate any part numbers you have found that would work. Supplier info would be great too.

    Thanks
    Chris
     

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