Troy-Bilt PTO Failure

Discussion in 'Mechanic and Repair' started by mattoxmkpb, Feb 12, 2010.

  1. mattoxmkpb

    mattoxmkpb LawnSite Member
    Posts: 5

    Man I'm hoping someone here can help me diagnose this.

    I have a Troy-Bilt GTX20 Garden Tractor (Model 13706). When the mower is started (cold) the PTO will engage fine. After a relatively short time with the PTO engaged, it will either cut out completely or the RPMs will drop extremely low for a minute or so until it stops. Once the mower has sat for a while and cooled, the PTO will engage again, but shortly after I have the same problem.

    There is also an odor as this process happens, which I believe is either electrical or metal on metal. I've already ruled out any problems with the electrical system/wiring UP TO the coil. I'm almost certain the problem is either with the PTO clutch or the coil, but I don't know how to diagnose which it is.

    Two additional pieces of information: The battery is being drained fairly quick and there is a fuse connected to the PTO switch which will occasionally blow. Neither of these problems presented themselves until the PTO issue began.

    I really need someone to come through on this. I have 4.6 acres to maintain. New PTO is around $450 and coil around $250 (best prices I could find on the Net). I have a new baby and can't afford to just buy parts HOPING it will solve the problem.
     
  2. Darryl G

    Darryl G LawnSite Fanatic
    Posts: 8,131

    Hmmmm....I'm certainly no expert on this. I'm more of a scientist than a mechanic, lol. What I'm wondering is if you have a bad spindle bearing or a pulley freezing up on you based on what you said about the rpms dropping. If something isn't spinning freely it would put a lot of load on the pto and engine. I can't see why a pto problem in itself would cause the rpms to drop. If you've got something with too much friction, it may be ok cold but as it runs and heats up and things expand the problem would get worse. It could just be a worn out bushing on a pulley or something. Maybe run it till it cuts out and then shut her down and see if any spindles or pulleys are heated up/locked up. How many hours are on this machine?

    Other thoughts guys?
     
  3. mattoxmkpb

    mattoxmkpb LawnSite Member
    Posts: 5

    Thanks for the quick reply, Darryl.

    Agreed, it seems like something might be binding, especially because of the smell. I've seen a lot of posts (not specifically about this model) concerning adjusting the air gap? The tolerances on this are extremely small, which leads me to think that it could be some kind of binding issue if the gap is out of spec. But this is where I start to get lost man...I'm not even sure it the clutch has an adjustable air gap. I think the cluth is made my Ogura and I've been trying to find some type of detailed information on how this thing works.

    When it shuts down, the whole front end where the clutch is located is so bloody hot I've not attempted to touch it to see if something is bound.

    I'm not at the machine where I can grab the hours, but it's an older model. I'll check when I get home tonight and post.
     
  4. Darryl G

    Darryl G LawnSite Fanatic
    Posts: 8,131

    I'd check the blade spindles and pulleys for the belts. Those bushings can wear out pretty quick and a bad or dry spindle bearing would cause some serious load on the pto and engine. I really don't know squat about the pto itself. In other words, start at the front of the line and work your way back to the pto. You don't want to replace the pto if there's another underlying problem which will just fry the new one. Kind of like changing a tube without removing the nail in the tire ;)
     
  5. shop22

    shop22 LawnSite Member
    Posts: 134

    If it's getting that hot it very well may be a bearing in the clutch starting to go. A spindle may be binding as well, but they are usually not temp related. when the spindle freezes up it never moves freely again. good luck.
     
  6. DT Lawn Care

    DT Lawn Care LawnSite Senior Member
    Posts: 850

    If the air gap is not correct, it can cause it to draw too much juice, thus blowing your fuses, and it can cause the PTO to cut off. Before checking this, take pressure off of your deck belts and make sure all of your spindles and pulleys are spinning freely, and greased well. If they are, I would find out your PTO air gap and adjust it to spec. You will need a set of feeler gauges to do so. Post back your results, and good luck.
     
  7. mattoxmkpb

    mattoxmkpb LawnSite Member
    Posts: 5

    So, when I started having the issue, my first action was to drop the deck and check it out. 60" deck with three blades controled by a central gear box on top of the deck. A drive shaft runs from the gear box to the PTO drive. The gear box is filled properly. I throughly cleanded the deck underside, sharpened the blades, greased all the zirt fittings. I can rotate the blades with slight pressure with a single finger, they spin like a champ.

    I'm thinking this is what you are all talking about when refering to spindles, pulleys and belts. If so, I've eliminated that possibility.

    Now, with this information, if any of you had to take a best guess.....?
     
  8. Darryl G

    Darryl G LawnSite Fanatic
    Posts: 8,131

    Yes, that's what I was getting at but didn't realize deck had a gear box. Just making sure there was no resistance on the blade end of things that could cause the problem. Good luck. I got nothing else.
     
  9. DT Lawn Care

    DT Lawn Care LawnSite Senior Member
    Posts: 850

    Yeah, I would say next step is to check your air gap on your PTO. Sounds like your deck is in good working order.
     
  10. mattoxmkpb

    mattoxmkpb LawnSite Member
    Posts: 5

    Thanks for the help guys. We're expecting more snow here in TN but I'll try to check the gap this weekend and post back. Hopefully this will help someone else down the road.
     

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