Why my deck shakes when I engage Blades

Discussion in 'Lawn Mowing' started by 1998tahoe, Aug 1, 2008.

  1. 1998tahoe

    1998tahoe LawnSite Member
    Messages: 233

    Today when I started mowing noticed upon engaging blades that the deck shook pretty hard. What could cause this?????
  2. OP

    1998tahoe LawnSite Member
    Messages: 233

    Could my deck belt be causing it???
  3. 1993lx172

    1993lx172 LawnSite Bronze Member
    Messages: 1,305

    Your blades might not be balanced properly or you put the washers that hold the blades to the bolt upside down. deck belt shouldn't't do that.
  4. JHLC

    JHLC LawnSite Member
    Messages: 147

    I have had the same problem twice with my super z. Both times I had a small piece of a stick get caught between the belt and the pulley. It was wedged in the pulley and acted like a speed bump for the belt. It vibrated like crazy! It took me forever to figure it out the first time. I hope this helps.
  5. CrewKut

    CrewKut LawnSite Member
    Messages: 193

    Could be any number of things. Bad spindle, bent or unbalanced blade, bad belt. Is there play in the spindle (pull plug wires first) when you try to move the blades by hand? Have you recently changed or sharpened the blades? Did you visually inspect the blade belts for wear and proper tension? Check the pulleys. Follow the advice everyone has given so far, chances are you will find the problem.

  6. OP

    1998tahoe LawnSite Member
    Messages: 233

    I think it may be the belt. My sonwas playing around shed where mower is stored. The belt tension lever got knnocked loose and the belt got on wrong side of tensioner. The PTO belt got extremely HOT when I went to engage the blades last Thursday. The belt is burnt pretty good could this be it???

    Also the blade washer referred to???? Did not know it mattered they look the same way...........
  7. Envy Lawn Service

    Envy Lawn Service LawnSite Fanatic
    Messages: 11,096

    I've given a great deal of instruction on here trying to describe this condition with the belt tensioner.

    It's very easy to have this happen (while greasing left spindle) and it is actually the #1 cause of people's unhappiness with the cutting performance of the deck..... simply because the belt gets mis-routed but will still run.... it just doesn't have full tension on the belt.... so it will slip and the blades will slow down without slowing the engine any.... which results in poor cut in more challenging conditions.

    This is also probably the cause for your shake.

    If not, and it is still shaking more than normal, there are two other possiblities to check. The most common is on of the 4 lift links the deck hangs from having no tension/weight carried on it... which allows the deck to teeter-totter diagonally. Re-level and Re-rake the deck, making sure all 4 points are carrying deck weight... problem solved.

    The other is.... you or someone WHACKED the deck HARD against something... and this took out a bushing... know how the deck is pulled from the front with those 2 a-arm links?.... Shake the deck front to back and side to side... look for "play" where the deck connects to these arms.

    The bushing inserts the axle rides on in those a-arms are about $3 each through Lesco.

    While you are at it, also check to be sure the problem tension pulley is mounted in the proper hole on the tensioner arm for your deck size.

    AND WHILE YOU ARE AT IT GETTING PARTS... GO AHEAD AND GET AT LEAST ONE OF THOSE PULLEYS TO HAVE ON HAND... if you notice, this is the only moving part on the machine that doesn't have a grease fitting. The pulley has sealed bearings... which will eventually fail and seize.

    That bearing is literally the only failure I have ever had period on one of these machines.
  8. 1993lx172

    1993lx172 LawnSite Bronze Member
    Messages: 1,305

    Some have a con cave shape to them. I did that once and the deck shook like you described but if your's are flat then never mind or they might be worn unevenly causing the blade to wobble
  9. ShadeTreeMower

    ShadeTreeMower LawnSite Member
    Messages: 1

    My mower deck has started to shake, but not immediately. It starts to shake about 20-30 minutes after I start mowing. It began this right after I had the blades sharpened. It sounds like I have the same problem described above, except my shaking isn't immediate.
    Rad418 likes this.
  10. BigGreen1

    BigGreen1 LawnSite Senior Member
    from Ohio
    Messages: 299

    Check the condition of your belt. Also see if your belt is twisted. I cannot see why it would take 30 minutes to show up. Bearing maybe??

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