New 930m deck belt slipping

Discussion in 'Lawn Mowing Equipment' started by lee b, Sep 25, 2013.

  1. lee b

    lee b LawnSite Fanatic
    Posts: 5,543

    I just bought a new 930m and the deck slows down too much in high grass. You can tell the deck is slowing down before the engine starts to labor. My old m665 with the orginial 7 iron never did this, you would stall the motor down before the deck slowed any. The old m665 would out mow this brand new 930m which has a bigger engine and much higher blade tip speed. I looked at the spring that tensions the deck belt and it doesn't put much pressure on the belt. Has anybody else run into this problem?
     
  2. Vecchio Lawn Care

    Vecchio Lawn Care LawnSite Senior Member
    Posts: 905

    My 920m has no problem at all even in high grass. Might have to slow a little but no belt slip
     
  3. Ridin' Green

    Ridin' Green LawnSite Fanatic
    Male, from Michigan
    Posts: 13,863

    Measure the spring. They relax a bit after you first start using the machine and get a few hours on it. It might need to be adjust. Measure the length of the spring coil from end to end, and only the actual coiled part from where it starts at each end. It should be 9".


    Also, don't be fooled into thinking the blades are slowing down in thick grass just because of the sound. If the grass is tall and/or thick, the clippings muffle the sound of the blades buzzing around and make it sound like the deck is slowing down.

    If none of that helps, let your dealer take a look at it. It may have a bad belt that is glazed over and not holding the sheaves like it should.
     
  4. lee b

    lee b LawnSite Fanatic
    Posts: 5,543

    It started doing it at .2 hours, spring is exactly 9". When it quits cutting the grass where the blades overlap and some of the rest is just laid over, the blades are slowing down. I took the spring off and can't see any way to adjust the length, thinking about adding another spring.
     
  5. Ridin' Green

    Ridin' Green LawnSite Fanatic
    Male, from Michigan
    Posts: 13,863

    Maybe your belt is slipping, but it could be several other things as well. It sounds though, like you may have gotten a belt that is out of spec for the app. I would have the dealer take a look at it or measure it to check. That would be covered under warranty. Is your deck a MOD deck?


    There's a nut on the end of the spring with a jam nut against it. Loosen the jam nut and tighten the inner nut to draw the spring tighter towards the end with the nuts, which lengthens the spring coil area.

    BTW- I run a 2012 Z950, so I'm not just shooting from the hip here.
     
  6. lee b

    lee b LawnSite Fanatic
    Posts: 5,543

    No adjustment on this spring, it's just a spring with 2 curled ends sticking out of it, pretty cheesy.
     
  7. Ridin' Green

    Ridin' Green LawnSite Fanatic
    Male, from Michigan
    Posts: 13,863

    So go to your dealer and buy the spring assembly from a Z930A. It will be adjustable just like mine is.
     
  8. Fuzzy1

    Fuzzy1 LawnSite Senior Member
    Posts: 320

    I have a 2013 Z920R with a 54" 7-Iron deck ... it has no spring adjustments ... it may be a feature that came/went with certain model # spans
     
  9. Ridin' Green

    Ridin' Green LawnSite Fanatic
    Male, from Michigan
    Posts: 13,863

    More like Deere doing what it always does- cheapening up everything they can after enough units have been sold to get a good rep out and no one is paying attention anymore to what is, or isn't there on the new models. I've owned a ton of Deere machines (my shops could be a commercial for them) over the last couple decades and have watched them do this time and again. :rolleyes:
     
  10. Ridin' Green

    Ridin' Green LawnSite Fanatic
    Male, from Michigan
    Posts: 13,863

    Here's a pic of my spring. You can see the adjustable nuts on the end towards the front (left end looking at it).

    100_1926.jpg

    100_1924.jpg
     

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