RESTOROB! How do I find a short?

Discussion in 'Mechanic and Repair' started by Stuttering Stan, Sep 16, 2006.

  1. Stuttering Stan

    Stuttering Stan LawnSite Bronze Member
    Posts: 1,504

    I have to jumpstart the mower to get it to start, but as soon as I take one of the jumper leads off the engine stops. I assume I have a short but where so I start?
     
  2. Stuttering Stan

    Stuttering Stan LawnSite Bronze Member
    Posts: 1,504

    25hp Kohler, the engine sounds like the choke is on and excessively backfires while idling. Is this indicitive of bigger problems? Thanks again Restorob and others who respond
     
  3. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022

    You need to start with checking the battery, If it is dead or has a blown strap it will not power the fuel cut-off solenoid to let fuel into the main jet to run. Putting a jumper battery on the unit and it runs is pointing to a bad (shorted) battery. Do you have a multimeter ?
     
  4. Stuttering Stan

    Stuttering Stan LawnSite Bronze Member
    Posts: 1,504

    I had the battery load tested and it is OK. What is the next step in finding a short?
     
  5. khouse

    khouse LawnSite Bronze Member
    Posts: 1,465

    i still would put a known good battery in it to test.
    while you have the jumpers hooked up does it still backfire at idle?
    clean your battery connections also.
     
  6. Stuttering Stan

    Stuttering Stan LawnSite Bronze Member
    Posts: 1,504

    Sorry for the confusion. I have 2 seperate mowers, each with their own problem. I messed up when i tried to post the at the same time.
     
  7. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022

    Along with what khouse posted check and clean the battery lead connection on the starter solenoid and your frame ground from the battery.
    To go much further I need the model and serial numbers off your unit, The engine spec. number may be helpful also.
     
  8. khouse

    khouse LawnSite Bronze Member
    Posts: 1,465

    are you saying that it doesn't sputter at idle? if so then try the 1st and 3rd line of my post above.
    and what restrorob said
     
  9. Stuttering Stan

    Stuttering Stan LawnSite Bronze Member
    Posts: 1,504

    Sorry for the confusion, hopefully this simplifies things

    Problem 1. Engine has to be jump started and then shuts down after I take a jumper cable off. Battery has been tested and is good
    Toro Z-Master Model Z325, 25hp Kohler, Frame model 74182, Serial 891466. Engine numbers are hidden due to the position of the engine in the frame


    Problem 2. Engine excessively backfires and sounds like the choke is on.
    Toro Z-master Model 255 25hp Kohler #CH25S, Family SKH725X1GSRA, Spec 68543, Frame model 74201.


    Thanks for all the help, sorry about picking your brain so hard, my week depends on these mowers.
     
  10. khouse

    khouse LawnSite Bronze Member
    Posts: 1,465

    problem #1 refer to post 5 and 7
    problem #2 does it backfire at all rpm's?
    how many hours on the engine?
    have you done a leak down test (maybe intake valve leaking)
    you really need to tell us more about problem #2
     

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