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Subject: Rotary cutter wobble

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Frank (WNY)    Posted 07-04-2018 at 07:22:11 [URL] [DELETE]        [Reply] [Email]  
  • Rotary cutter wobble
  • I finally ran the 5 ft King Kutter that I bought used a few years ago yesterday. I started in the pasture that I needed to mow. When I started it, it seemed like it was running fairly smooth, but since this is the first time that I have ever used one, I could have thought that the operation was normal. I mowed about an acre, the size of the pasture. and then took a break. I moved on to the next pasture, and ran it for about 15 minutes and when I turn around, I noticed the whole deck wobble side to side. I shut everything down and looked under the deck. but didn't see any problems. I know that the gearbox has a slight leak on the input side around a lower bolt and after running. there is some oil running down the output shaft. I checked to make sure it was a still full. I am planning on taking off the blades as soon as I get a socket set that will fit and weighing them for balance. Is there any thing else I should check? The ORC seems to work fine, but I notice a small wobble in it. Could that translate into a big wobble in the deck? Thanks

    Tim Daley(MI)    Posted 07-05-2018 at 05:14:32 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Rotary cutter wobble
  • Check the gear box to ensure the mounting bolts are not loose or missing. Next, be sure it isn't the PTO shaft causing it. If it is a brush hog, it should have the stump jumper feature. That is the blade is actually two separate pieces that pivot horizontally back so if an obstruction is encountered, the blades swing back clear of it so as not to damage the gear box. The worse case scenario would be if indeed a large obstruction was hit without a stump jumper feature, the main drive gear in the box got broken and is now big job to replace.

    Tim Daley(MI)

    Frank (WNY)    Posted 07-05-2018 at 07:15:14 [URL] [DELETE]        [Reply] [Email]  
  • Re: Rotary cutter wobble
  • Hi Tim,
    Are you talking about the PTO shaft inside of the tractor, or the driveline going to the gear box? The ORC wobbles a bit, but I don't know if it is too much to cause the deck to wobble as much as it does.
    I took a better look at the blades, and see that the blades are locked and don't pivot, but are not lined up straight with each other. I am going to take them off to weigh them and free them up so they pivot. The seals are leaking on both input and output shafts, so I plan on replacing those as well.

    Frank (WNY)    Posted 07-04-2018 at 15:14:19 [URL] [DELETE]        [Reply] [Email]  
  • Re: Always something else!
  • With the cutter waiting for me to get to that, I decided to use the box blade that has been patiently waiting to work for the first time. I took it out to the horse training area and started to run it around. At about the third pass, the engine started to run rough and stalled. I started it and had to use the choke to keep it running. (I haven't needed to use the choke to start it let alone hold it out to keep it going) Needless to say, I checked the archives and see it seems to happen to others now and then. So something else to trouble shoot and fix. I just replaced the sediment bowl shut off assembly and the carb filter this spring, but who knows what gunk may have come out of the tank. Oh yeah, and I am on vacation this week!

    K.LaRue-VA    Posted 07-04-2018 at 07:44:32 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Rotary cutter wobble
  • Usually what you suspect, out of balance blades, but when it happens suddenly, I suspect something wrapped around one blade axle that locked it up so it can't swing free. That could be a strand of wire or nylon cord. Before getting tools out make sure blades swing free.

    Frank (WNY)    Posted 07-04-2018 at 09:35:38 [URL] [DELETE]        [Reply] [Email]  
  • Re: Rotary cutter wobble
  • That is another reason that I need to get the blades off. Both are either rusted solid to the stump jumper or the bolts are tightened to the point where neither can swing. I knew this before I started, but thought that once I started, they might break loose. they are both stuck straight out from the center. The blades had surface rust on them, cutting an acre cleaned them up. The are not sharp but look like they both have had little use. I don't think they have ever been sharpened before.

    r geiger    Posted 07-04-2018 at 09:52:19 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Rotary cutter wobble
  • I would hit them with a lot of PB blaster or something similar.

    Frank (WNY)    Posted 07-04-2018 at 11:11:12 [URL] [DELETE]        [Reply] [Email]  
  • Re: Rotary cutter wobble
  • I parked it in the garage and started soaking them with PB Blaster yesterday. Every couple of hours I smacked them with a 4 pound hammer. One of them moves up and down a hair. Eventually something has to give...

    K.LaRue-VA    Posted 07-05-2018 at 07:51:20 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Rotary cutter wobble
  • My 5 foot cutter has a similar problem with rotten hardware. The remains of the stump jumper pan rusted and came loose. After removing that, there is just a "T" bracket and swinging blades under there. My blade hardware is so rotten, the only way it's ever going to move is with a cutting torch. My functional problem was the blades were loose and flopping around. They would sag and hit the ground or pop up and hit the top deck. Since loosening or tightening the hardware was not happening, I turned the whole thing on edge, and added weld metal to the face of the "T" bracket until the blades were tight enough not to flop around. While I had it on edge it was easy to sharpen and balance the blades. Park the blades horizontal, the one that starts to drop is heavy, grind a little metal from that one. When I got done, the cutter ran so smooth, the only sound you could hear was air whistling past the blades.

    Last time I sharpened/balanced the blades, I left it hooked to the tractor, removed the drive shaft, removed the top link, removed the bolt from the tail wheel bracket, then raised it up, and put jack stands under the front. That gave me enough room to work, and enough angle on the deck to balance the blades. I have been keeping my blades sharper than they are really supposed to be since I'm only cutting grass and weeds now.

    Frank (WNY)    Posted 07-05-2018 at 10:05:04 [URL] [DELETE]        [Reply] [Email]  
  • Re: Rotary cutter wobble
  • Thanks for the information. The metal on this King Kutter doesn't look that bad. Most of the paint is good and there isn't a lot of rust. The blades don't look like they have seen much use. The stump jumper looks pretty solid. I am hoping my impact wrench will vibrate the nuts loose. I am waiting for some new seals to come so I can stop the leaking. I am going to try to chain the deck up against a tree to get the stump jumper off to replace the output shaft seal.
    I appreciate the advice.

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