Scag 36" dual hydro walk behind with vibration coming from hydro units

Discussion in 'Mechanic and Repair' started by airsoft1779, Aug 2, 2011.

  1. airsoft1779

    airsoft1779 LawnSite Member
    Messages: 152

    Just got this used mower and have put about 15 hours on her. I was in the middle of a lawn and this fairly noticeable vibration appears almost instantly through the sulky. I shut off the blades and drive it around and it is still there. Finish the lawn and then go home.

    What I have learned so far is this- The vibration increases as I go uphill, and decreases alot when on somewhat flat grass or a small downhill ( haven't tried a big downhill yet). And I know it has to do with the hydro units..

    What I have not tested is if it is coming from just one pump or motor or both. I called my mechanic and he said it is probably the hydro motor pinion( or some pinion gear) that is going out. What I think I am going to do is do some turns and try and figure out which side it is, and if it doesn't change, then I am guessing it has to do with the belts or pullys that drive it? And if it stops as I turn, I am guessing it has to do with the hydro and not the bets.

    But it still pulls uphill normally and the speed hasn't really changed. My mechanic just said finish up the jobs for the week as long as I am mowing on flat land and then bring it to him. Thoughts on this? Is it safe or am I doing more damage then good?

    And I am not sure on what year, guessing around 2003-2005. Dual hydro 36" fixed deck with a kohler engine, pistol grips

    Any tips or help is greatly appreciated.

  2. T-Trim

    T-Trim LawnSite Member
    Messages: 204

    check the bolts holding the engeine to the mower. Sound crazy but do it
  3. airsoft1779

    airsoft1779 LawnSite Member
    Messages: 152

    alright will check that any other tips or ideas?
  4. piston slapper

    piston slapper LawnSite Platinum Member
    Messages: 4,327

    Like T-Trim said....I would check for loose engine bolts first...
    Also , while your under the mower check the belts and idler pulleys.
  5. airsoft1779

    airsoft1779 LawnSite Member
    Messages: 152

    alright, haven't had to much time today to look at it but have made progress, i hope.. I turned it on and put it in neutral and just let it sit there while I looked under machine. I noticed the pulley that put's tension on the drive belt to make more contact with the engine's pulley is loos. The guide/metal piece that holds the pulley in place and puts pressure on it is loose, causing the spring loaded pulley to wiggle back and forth very fast, thus causing the drive belt/pulley to vibrate aggressively and what I hope to be causing the vibration..

    Tomorrow morning before I go out I am going to tighten it back into place and pray to god that it works.. But I am pretty sure this is it. I mean the pulley is moving back and forth pretty fast..

    Letme know if this is a good assumption, and please tell me yes haha.

    Thanks Jacob
  6. airsoft1779

    airsoft1779 LawnSite Member
    Messages: 152

  7. airsoft1779

    airsoft1779 LawnSite Member
    Messages: 152

    No one know's what could be causing the tension pulley to be moving back and forth violently?.. belt looks fine. bearings are fine. eveything is screwed on tight. I did tighten the engine bolts but that didn't solve the problem..
  8. ed2hess

    ed2hess LawnSite Fanatic
    Messages: 14,199

    I was going to post earlier and suggest that there was no problem with a little vibration. There is no damping on that extension spring so any defect in the pulleys or belt will cause the vibraton.
  9. airsoft1779

    airsoft1779 LawnSite Member
    Messages: 152

    Well the thing is, I didn't feel the vibration before. It came on almost instantly and, I may be wrong, but this belt looks like its going to snap it's vibrating so violently. It almost looks like it is going to come off the pulley's as well.
  10. Shultz

    Shultz LawnSite Member
    Messages: 83

    I dont know what might be goining on on your machine. I just had a pump bearing start go out on a scag tt, and other than the vibration in the levers and a little hesitation/chatter in reverse, i never would have known.

    For what its worth, check the hydro tank res. with a magnet for metal filings/shavings.

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