sudden and violent PTO engagement with new Kubota MX5800

[rbtjr]

We have a Kubota MX5800 with about 14 hours on it. The MX PTO is engaged electrically by pressing a switch that locks in place until you press it again to disengage the PTO. I have engaged the PTO five or six times so far using our brush hog. Each time the PTO engagement has been very abrupt and pretty violent. The PTO engagement is much more violent that I have experienced with prior tractors for which the engagement was via a clutch you could engage very gradually and smoothly. The PTO engagement on our new MX makes the rotary mower shake badly and violently. The mower is new from Everything Attachments and I have no reason to believe that the mower is the problem. Do any of you owners of Kubota MX tractors that have the electric PTO engagement system have a similar problem? If so, what is the fix? If not, I would like to know that your PTO engagement works well so I will have some data to tell my dealer about when I ask for the fix. Thanks in advance for your feedback.

 

[k0ua]

What RPM are you engaging the PTO?.. You should always engage the PTO just above idle with the cutter raised a bit to make sure there is nothing under it for the blade to hit. See if this helps. But electrically actuated PTO's do engage more violently than what a human can do with slowly letting out the clutch. But if you have the RPM's up it is really violent.

 

[ovrszd]

I'm afraid that's the nature of the beast. Do your engagements at engine idle to minimize the shock to the cutter or any other PTO attachment.

 

[Coyote machine]

Got to go with lowest engine RPMs for PTO engagement possible to minimize torque shock to your mower AND your tractor's drivetrain.
You could also ask Travis at EA; he knows Kubotas and his hogs/mowers too. He might be familiar with the issue you describe with the Kubota model you have....
Can't hurt to ask..
The only other thing that comes to mind for me is the faint possibility that your PTO shaft is out of balance and causing some issues because of it's knuckle joints being out of sync - but it's remote at best....
Once it gets going to speed, does the shuddering stop?

 

[rbtjr]

Yes, I always engage the PTO at the lowest possible RPMs, and with the implement raised.

Good point about asking Travis. I will do so.

Yes, the shuddering stops when the PTO gets up to speed. But today the engagement was so violent once that the tractor shut off and wouldn't start even with the PTO switch turned off. I disconnected the PTO shaft to the mower and then the tractor started.

Thanks for the feedback.

 

[RandyT]

I know what you are talking about. My DK45S is abrupt also. Engage rotary cutter at idle and cringe, with the slamming and shaking until it gets up to speed. My tractor idles at about 1000, and at 1500 I can shear a 1/2 grade 2 bolt used as a shear bolt.

 

[arizona98tj]

I have a Massey Ferguson with a similar electric PTO clutch. Starting my brush mower....it is almost scary given how bad it sounds. In contrast, starting my PTO wood chipper is about as smooth as can be. Go figure.

 

[David_Kb7uns]

Only other ideas is, what regulates the pressure or flow in the PTO circuit and is there a way to put a flow restrictor in to slow down engagement.

Will it get better after things break in and does the type or weight of hydraulic fluid have anything to do with how it engages?

David

 

[rbtjr]

Only other ideas is, what regulates the pressure or flow in the PTO circuit and is there a way to put a flow restrictor in to slow down engagement.

Will it get better after things break in and does the type or weight of hydraulic fluid have anything to do with how it engages?

David

Good questions. I don't know if there is an adjustment but I'll find out. The hydraulic fluid is what came in the tractor. I had a leak which was fixed by the dealer, and the hydraulic fluid was topped off with the recommended fluid. I'm going to investigate some on my own, ask the dealer what can be done, etc. I'll report back about what I learn.

 

[nybirdman]

Check to see if the BH blades are "straight" before engaging.