PTO clutch trouble

Discussion in 'Lawn Mowing' started by wattsup, May 16, 2002.

  1. wattsup

    wattsup LawnSite Member
    Messages: 123

    I have a Warner Mag-Stop clutch on a 25hp Kohler. I was mowing today and started smelling something funny. I shut the mower off and checked the fan shroud to see if it was clogged, and all good to go. So I started again andwent about 100 ft without the blades engaged and all the sudden a puff of smoke came from the engine area. I shut down the engine and looked around. The bearings inside the clutch had melted and some shot out of the housing. I started using doubles this year, but was not using them when it happened. As directed by my owners manual I engage the blades at full throttle. Any help/suggestions will be greatly appreciated. By the way it is still under warranty.
  2. wxmn6

    wxmn6 LawnSite Member
    Messages: 163

    Really? Your mower manual said to engage the blades at full throttle?

    Normally I would engage the blades at half throttle then push it up to full throttle. That way it reduce clutch slipping and from heating.

    Bring it to your dealer and have it repaired. When you are there, ask them if you are supposed to engage the blades at half or full throttle.
  3. UGA

    UGA LawnSite Senior Member
    Messages: 326

    I was reading a post today about a guy who says if you pull your chock out a little when you engage the blades it won't bog down the engine as much if at all and I think he said it is easier on the clutch as well. Call me later. I know you haven't been cuttin' today. It's been a monsoon out there!
  4. Dennis E.

    Dennis E. LawnSite Senior Member
    Messages: 349

    but the dealer I worked with for a number of years said to engage the PTO over a "smooth" area such as the street or parking lot and then move into the turf area and move to WOT.
    Of course a person cannot always follow this but 1/2 throttle and engage PTO and then to WOT seems sensible.Saves a lot of wear and tear IMO.
  5. Runner

    Runner LawnSite Fanatic
    Messages: 13,497

    I alway engage mine with the deck up if it's in uncut grass. Also, speaking of wear and tear, not only should the blades be engaged at a lower rpm, but because the clutch also acts as a brake, they should ALSO be disengaged at a lower rpm. I alway shut mine down to an idle first, give it a moment or two to slow completely down, and then disengage the pto.
  6. FrankenScagMachines

    FrankenScagMachines LawnSite Platinum Member
    from IN
    Messages: 4,739

    Well, I guess you know this, but electric clutches last longer if engaged at idle or low engine rpm's. Then, after they're engaged, run the engine up. Only engage at low speed. It will bog the motor, but causes no damage to motor, and lets the clutch go from 0 to 1500 or 2000 rpm's instead of 0 to 3700 rpms, making it last longer.
    Also, I think you can get heavier duty clutches. I assume that they're giving you the right one? But a heavier one would be better for doubles. Yes, they are adjustable. Most have 3 bolts around the outside that have springs on them. You tighten or loosen the nuts accordingling to how you want it to be.
  7. Pelican

    Pelican LawnSite Member
    Messages: 164

    Consider the physics involved: Mass in motion tends to stay in motion; Mass at rest tends to stay at rest. The clutch is helping you to overcome this law. When you engage the clutch, the friction lining uses the mass of the moving flywheel and power of combustion to overcome the mass of the motionless blades, spindles and belts to put them in motion. When you engage at full throttle you are putting a tremendous amount of energy through the clutch to get the blades to turn at the same speed and excessive slipping occurs. The proper way to engage your clutch is at the lowest speed to prevent stalling.

    Another comparison: You don't (or shouldn't) engage your truck's clutch at full throttle and expect it to last for any length of time. The mower's clutch is made of the same materials but is electrically activated instead of by pedal.

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