48" Scag W/B - blades will not engage, please help!!??!!

Discussion in 'Mechanic and Repair' started by epheus, Jan 21, 2007.

  1. epheus

    epheus LawnSite Member
    from texas
    Messages: 5

    Hello all, I really need your help!

    I purchased a Scag 48" walk behind from a private party (sat in his garage for a year, used very very little) a few months ago, and its been working great for the last ~35 hours.

    But, in the middle of a job, the blades suddenly stopped working. Here is what I have done:

    1. kept trying the blade engage switch, occasionally the blades would come back on, making a squeel initially then running without issue.

    2. Now I am getting nothing at all, when i turn on the switch the clutch does not seem to engage, nothing is spinning except the drive belt.

    3. But, if the blade engage switch is on, and if i let go of the safty bars on the handle? the mower dies like always, its acting as though the blades are engaged.

    4. I greased all the blade spots, just in case, and checked to see if i can manually move the belts, i can.

    5. checked the cabling, seems fine.

    Please help, any ideas here, I really need this machine running and cant afford to buy a backup.

  2. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    First check for voltage at the PTO clutch connector plug with a multimeter, If voltage is present then check the adjustment as below.

    If your clutch looks like the one below there is three slots in part # 5 to insert a 0.012 feeler gage and adjust the three nuts until you feel a little drag on the gage. But only move each nut a little at a time because one will throw the other out and go around to each slot a couple times to get it even.

  3. epheus

    epheus LawnSite Member
    from texas
    Messages: 5

    Thanks man, went and just bought a PTO switch, now it works. I dont really get it though because why would the mower die when the PTO was engaged if the switch wasnt working... sorta quirky.
  4. lawnpro724

    lawnpro724 LawnSite Silver Member
    Messages: 2,201

    had to replace switch on mine a couple years ago then last year clutch went out and had to replace that.
  5. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Most PTO switches serve two functions, They have contacts to engage the clutch and contacts for a safety cut-off . In your case the contacts that activate the clutch were bad (probably burnt) but the safety cut-off contacts were good. That's why the engine would shut down with the switch on when letting go of the bar.
  6. flys-lo

    flys-lo LawnSite Member
    from OH
    Messages: 1

    Sorry to revive an ancient thread...

    Is there a way to "jump" the switch to see if the blades will engage and prove the switch is bad?

    I have a 52" WB hydro and the blades stopped during a mow. I turned the spindles manually and they started again for another few minutes and now nothing will get the blades turning. Wiring all seems intact, unit has 25 hours and is 4 years old (homeowner).
  7. Sharpcut 1

    Sharpcut 1 LawnSite Senior Member
    Messages: 452

    Yes you can, but I can't remember the color of the wires. It might be the 2 orange wires on a Scag. Like Rob said, you need at least a test light to see if you have voltage into the switch, and jump that wire to the wire going down to the clutch. Just make sure you don't jump to a ground or you'll have instant wire meltage. Or disconect wire down at cluch, move out of the way of spinning parts, have someone press the OPC and lift the switch. If it lights up, switch is fine, it's either the ground on clutch, or clutch.
  8. Chevy z71

    Chevy z71 LawnSite Fanatic
    Messages: 12,052

    I know this is not the right place to put this and im going to get yelled at but does anyone know how to get the belts on a scag to stop squeaking when you try to turn i have put wd on them but it just starts to do it again after like 2mins.

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