Mowing Violent start of rotary cutter

[Johnjudge007]

I have a DK55c with a Rhino rotary cutter/mower and it shakes violently at start-up, someone told me that is normal

 

[MichiganIron]

If you were close enough to the shop, we'de let you borrow a slip clutch to try it out. We ain't guessing about this, we did it , tested it, and have used it on several DK tractors for our customers with rough cutters and finish mowers. The little slip at start up is just enough to soften some of the kick-in. With a 72" rough cutter, some customers were shearing pins just on start up. Rough cutter blades tend to congregate to the same side of the deck when you shut them down. At start up, you have to get the blades moving so the angular momentum throws the blades back out in balance. With the e-hydro engagement, it causes a pretty violent start since you can't feather the pto. The slip clutch just takes a little of the "shock" out of the inertia needed to get the blades moving. Gives it a small amount of feather. They dont' offer the same feathering as a clutch but they also don't slip enough to cause a performace problem with the implement. Quite the contrary, they tend to cause th rotory implement to run smoother and protect the tractor pto clutch from impact loads.....

.....BUT............

 

[radman1]

If you were close enough to the shop, we'de let you borrow a slip clutch to try it out. We ain't guessing about this, we did it , tested it, and have used it on several DK tractors for our customers with rough cutters and finish mowers. The little slip at start up is just enough to soften some of the kick-in. With a 72" rough cutter, some customers were shearing pins just on start up. Rough cutter blades tend to congregate to the same side of the deck when you shut them down. At start up, you have to get the blades moving so the angular momentum throws the blades back out in balance. With the e-hydro engagement, it causes a pretty violent start since you can't feather the pto. The slip clutch just takes a little of the "shock" out of the inertia needed to get the blades moving. Gives it a small amount of feather. They dont' offer the same feathering as a clutch but they also don't slip enough to cause a performace problem with the implement. Quite the contrary, they tend to cause th rotory implement to run smoother and protect the tractor pto clutch from impact loads.....

.....BUT............

Although what you say may work, it is not how a slip clutch is designed to work. If I start the mower at 1/2-2/3 throttle and allow the slip clutch to slip, to get the mower going, how is the slip clutch going to perform at full throttle under a heavy load? It will slip excessively and burn out the clutch. I think the reason it works for your customers, is because they mow relatively light duty grass/weeds and don't make the clutch slip at full pto speed. I would guess, the hardest the mower ever works is on start up for your clients. I have several attachments with slip clutches for CUTs and Ag tractors and would never allow a slip clutch to be so loose to slip on start up.

 

[gauthier]

radman,I never start my pto at 1/2 or 2/3rds throttle,start at idle.[Maybe thats not what your doing either,but from last statement,not sure]

 

[roger 4400]

Hi! On Massey Ferguson 1600 serie( mine is a 1643) there is a special button that we can depress if we want a **gentle ** start of the pto. We depress it and then put the electro magnetic pto start ( and cancel it after it is running for a few seconds). It gives a softer ( more progressive) start to my mower but it still gives a shock . I do not know if that can be put on yours?? But the best way is to start it at the lowest iddle possible ( in my case) . Good luck. Roger.
I put a photo, it is the amber yellow square button left of the yellow pto switch on the right side of the steering.

 

[Dargo]

Hi! On Massey Ferguson 1600 serie( mine is a 1643) there is a special button that we can depress if we want a **gentle ** start of the pto. We depress it and then put the electro magnetic pto start ( and cancel it after it is running for a few seconds). It gives a softer ( more progressive) start to my mower but it still gives a shock . I do not know if that can be put on yours?? But the best way is to start it at the lowest iddle possible ( in my case) . Good luck. Roger.
I put a photo, it is the amber yellow square button left of the yellow pto switch on the right side of the steering.

Well, ya put your steering wheel right over that magic switch! I figured someone would have some sort of 'soft start' switch or setup by now. Good info....bad pic. (of the button)

 

[roger 4400]

Well, ya put your steering wheel right over that magic switch! I figured someone would have some sort of 'soft start' switch or setup by now. Good info....bad pic. (of the button)

As you said , good info bad pics... nothing is perfect:laughing:
I had taken that photo a few month ago and used it today. But at least you got the idea . Have a nice day sir .

 

[Dallas_Lilly]

On my Montana if you load the hydraulics up with the loader curl it softens the blow allot. Just curl the bucket all the way up and hold the pressure against it, then engage the PTO.

 

[Dargo]

On my Montana if you load the hydraulics up with the loader curl it softens the blow allot. Just curl the bucket all the way up and hold the pressure against it, then engage the PTO.

Sounds to me like another potential good idea. I only say 'potential' since I can't try it out. Being wimpy and afraid of breaking my 50 hp rotary cutter gearbox with 78 PTO hp, I went with the old fashioned manual lever.

 

[DK35vince]

On my Montana if you load the hydraulics up with the loader curl it softens the blow allot. Just curl the bucket all the way up and hold the pressure against it, then engage the PTO.

Can't hurt to give that a try next time I have the cutter on.