Help LZHP Problem

Discussion in 'Lawn Mowing' started by Florida 5 Star, Jul 25, 2005.

  1. Florida 5 Star

    Florida 5 Star LawnSite Member
    from Florida
    Messages: 92

    I have a Lazer ZHP 48" 21hp Kaw its under 3 years old with just 300 hrs on the unit. (hydro unit was serviced at 250hrs by the dealer)
    My problem is that when working with the blades engaged and using the hyros the unit stalls. I can restart the unit and re-engage blades then it's fine going straight but when I attempt to drive either left or right in the unit stalls again. I have been able to stop the stall on occasion buy bringing the hydo's back to a neutral
    I have brought it to the dealer where I purchased and explained the problem to the service tech. They were unable to find any problem even after running it for a couple of hours. However 3 hours later when services was closed it reappeared.
    Ambient temp was about 95 (checked the motor fins they were clean)
    oil was checked (WNL)
    Hydro oil was checked (WNL)
    Fuel filter was fine but I replaced it any way
    Any ideas?
    Thanks in advance
    Regards Paul
  2. jimslawns

    jimslawns LawnSite Senior Member
    Messages: 283

    Does the machine stall only when turning? One direction or both? Did it do it prior to having the hydro serviced?

    I wonder if the seat saftey is disengaging when you shift weight on the seat?
  3. SproulsLawnCare

    SproulsLawnCare LawnSite Senior Member
    from IN
    Messages: 365

    If this problem showed up after the service, it could be possible that the service tech used the wrong fluid or filter. I wouldn't think that it would effect it starting again though.
  4. Envy Lawn Service

    Envy Lawn Service LawnSite Fanatic
    Messages: 11,087

    I went through this on a Yazoo/Kees mower. It began by just bogging a bit. From brand new it always seemed like the hydros posed a very heavy load on the engine. You could hear the govenor kick it just driving it up a 10-15 degree slope with the deck off. With the deck on, it would bog down. It got worse and worse. But then one day, at 74 hours on the meter, I was mowing along a ledge, and when I turned up the hill the machine completely stalled out and the engine died. When this happened, the machine rolled backwards with me on it and over the ledge. I was able to get off at the last second, saving myself from certain death, and physically helping the machine avoid rollover.

    In the end, it turned out I had engine problems and hydro problems. But the locals were not able to ever properly diagnose either of them.

    But the first question I have to ask you is....
    Does it stall with the pto off?

    I'm going to take the optimistic stance on this since it's an eXmark mower and a Kawasaki engine.... and say my first guess is that you simply have a bad coil on the engine. Pull both of your spark plugs and compare them. Sometimes that will indicate the problem.

    Understand that the PTO clutch is electric and pulls power from the system. So if you have a bad or weak coil, the symtoms more obvious when power is being pulled away and when the engine is under more load.

    I'm hoping the issue is this simple for you.
  5. TClawn

    TClawn LawnSite Silver Member
    Messages: 2,036

    is this unit stored out side?

    if I may add my .02,

    I think it is possible that you are tripping the operator presance safety.

    the other possibility that crossed my mind, was that the clutch bearing were rusted or almost siezed, I have seen a couple cases of this, and it sounds like what you're talking about. on a machine under three years old, it does not seem likely.

    the only other thing I can think of, is that something is binding or rubbing creating heavier load, have you changed the deck or hydro belts recently? they'd prolly be shreded by now if they were rubbing, butt that about all I've got from personal experience.

    I like envy's electrical theory, if the dealership didn't drive around too much with the blades engaged, or in growth, they may not have noticed anything.
  6. Florida 5 Star

    Florida 5 Star LawnSite Member
    from Florida
    Messages: 92

    No problems at all prior to serviceing the hydro's ,but its been 60+ hours since service so I doubt that is it
    No new belts
    I checked the sensor under the seat and with my fat A** on the seat it not a doubt the sensor is working, I aslo bypassed the sensor and it still does it.
    It seems only to do it under load but more so with the left hydro

    I will pull the plugs in the AM and check
    How do I check the output on the Coil?
  7. Envy Lawn Service

    Envy Lawn Service LawnSite Fanatic
    Messages: 11,087

    If you bypassed the sensor, that can certainly be marked off the list.

    Pulling the plugs might show you that a coil is bad.
    But then again it might not.

    Any shop should have the testers to check the coil output.

    However, if this seems to be related to one side of the hydros, it doesn't sound so good and simple. If it will duplicate this from the left side with the deck off, then there is more of a concern.

    But, while on the subject of safety switches, it wouldn't hurt to bypass some of the ones on the motion control one at a time. The one on the park break and then the lever kill switches.
  8. ProLawns

    ProLawns LawnSite Senior Member
    Messages: 476

    I'll take a stab at this. I have a Toro ZTR with a 23 Kaw. I replaced the fuel filter when it started starving for fuel and stalling. The filter I replaced it with had a really tight element and it clogged up within a week or so. The dealer told me that my 23 Kaw. draws a lot of fuel and certain filters won't allow enough fuel to pass through continuiously to supply the engine. I went to a different brand that he recommended and that solved the problem. It's odd that yours only does it when turning but there is more load which requires more fuel when turning. Go to a larger filter which has more surface area on the element. I hope it's something this simple.
  9. riches139

    riches139 LawnSite Senior Member
    Messages: 369

    My 25 Kawi did the same thing. Bogged a couple of times, then died.
    Changed fuel filter, then was fine.
  10. Florida 5 Star

    Florida 5 Star LawnSite Member
    from Florida
    Messages: 92

    Guess what when you fire an employee check your fuel.
    Both tanks had several hand fulls of sand it even plugged the new fuel filter solid
    Ohh well live and learn just weird that the service tech missed it as well
    Thanks to everyone for all their help

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