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Strange Problem with Exmark: Cut blades on, engine turns off...

Discussion in 'Mechanic and Repair' started by Fubba, Nov 19, 2007.

  1. Fubba

    Fubba LawnSite Senior Member
    Posts: 356

    Happened today. Let me start off by saying that it ran great last week. It's a Exmark Lazer Z HP 23hp 52". Last day I used it was Friday. Everything ran perfectly, the way it has since I bought it. I bought the mower August 2005. (Ironic how the warranty runs out huh) It now has right at 500 hours on it. Most of them happening this year. I get on it today, and the battery is dead. First time that's happened. I carry a small jumper, so once I jumped it off, I hopped on it to do a yard. I cut the blades on, drive about 1/4 pass, and the mower cuts off. So I check gas (level's fine), and jump it off again. This time, I cut the blades on and once the blades get up to speed, the mower begins to shut off. I then push the blade switch back in, and the mower runs fine. I did this several times. The mower will not run with the blades on. I know the parking brake is linked to this switch, but so are other things, and I would think if something was amiss there, then other things would not be working right. Could it be the PTO switch itself? Any ideas? Remember, it also sucked my battery dry over the past two days, whatever it is.
  2. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023

    First thing you need to do is install a new battery, After all it is 2 yrs. old ?

    Once you get a new battery installed check your charging system at the battery with a multimeter to make sure it operating properly.

    My guess is a bad cell in the battery and the clutch was drawing too much voltage and the fuel cut-off solenoid was shutting off the fuel flow to the main jet.
  3. Fubba

    Fubba LawnSite Senior Member
    Posts: 356

    Hmm...didn't know it would do that. I will definitely get a new battery. Could you explain how to check the charging system? I have a multimeter.
  4. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023

    Set your meter on DC voltage and put the red test lead on the positive battery post black on negative. Start the engine then give it full throttle, It should read between 13.5 to 14.8 if properly working.
  5. Bill Kapaun

    Bill Kapaun LawnSite Senior Member
    Posts: 921

    Not one to disagree with Rob very often, but I kind of see a possibly different scenario-
    IF the alternator was failing to charge last Friday, the battery may have had enough capacity to get you through the day, but was dead the following Mon. (today)
    What I would do, is charge the battery for a couple hours and then test the Voltage with the mower running full speed. It should be up around 14+ or so.
    That should let you know if the charging system is working. If it is, pay attention to Rob!:)

    A 2 year old battery IS on the suspect list.
  6. Grouch

    Grouch LawnSite Member
    Posts: 36

    Check your seat switch. If the unit thinks no one's home, it will shut down when the PTO is engaged.
  7. Fubba

    Fubba LawnSite Senior Member
    Posts: 356

    I put the new battery in. Hooked the multimeter up to it and got in the range of 13.6-14.2 everytime. Looks like the 2 year old battery was the culprit. Thanks for the help!
  8. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023

    Good to hear that's ALL it was......
  9. thelawnboss

    thelawnboss LawnSite Member
    Posts: 89

    you may not believe this but it may be simple, as i have had this same problem on mine. What i found was this, sometimes when i start the mower, the key will actually stick in the "START" position, when this happens, you start the blades or take off the parking brake the mower dies. I dont know that this is your problem or not but something to look for. Never know. Good luck.
  10. Adam's Lawn and Garden

    Adam's Lawn and Garden LawnSite Senior Member
    Posts: 306

    I had something similar to this happening to mine a while back, the mower shop said it was a tilt switch that they don't use on mowers anymore for this reason. He by passed it, hasn't shut off like that once.


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