M4 PTO engagement

[skipperbrown]

I've got a new M4 and I'm running a 7' cutter behind it. When engaging the PTO, stopped, at an idle, with the little yellow knob, there is no transition between off/on. The PTO slams on and the start of the blades is rather violent shaking the whole tractor. I'm coming from an 80hp New Holland that had a mechanical engagement and you could feather the startup of the PTO. It was so gentle, the engine rpms wouldn't even change. With this M4, no matter how slowly you twist the PTO button, it goes from off to on instantly. Anyone else having an issue with this?

 

[mcmxi]

I have an M6060 and run a 7ft Land Pride rotary cutter in the form of an RCR1884. Like you I engage the PTO at idle and I would say that the engagement can be a little rough, but it depends on where/how the blades are orientated when they came to a stop. Overall I wouldn't say that the engagement is "violent" but it's certainly not smooth.

Since I've never owned and operated a New Holland I have no point of comparison, but if the PTO on your previous tractor would slowly come up to speed because you could mechanically "feather" the engagement then I would say that it's a very nice feature to have. Have you tried any other NH tractors that have an electrical on/off PTO button? Just wondering if all tractors with electric PTO engagement will do the same as my M6060 and your M4.

 

[Roadworthy]

Try leaving your engine at idle. Depress the clutch and engage the PTO. You can then ease the clutch out smoothly bringing the mower up to speed. Now bring the RPMs up to PTO speed. When disengaging the PTO depress the clutch first. That is the sequence told to my by my Kubota mechanic. It works for me.

 

[mcmxi]

Try leaving your engine at idle. Depress the clutch and engage the PTO. You can then ease the clutch out smoothly bringing the mower up to speed. Now bring the RPMs up to PTO speed. When disengaging the PTO depress the clutch first. That is the sequence told to my by my Kubota mechanic. It works for me.

"It works for me" ....

So you know this from personal experience with a manual transmission Kubota?

For what you're saying to be correct, the rotation of the input shaft to the PTO hydraulic clutch pack would have to be dependent on whether or not the hydraulic transmission clutch is engaged?

 

[JasonW]

Try leaving your engine at idle. Depress the clutch and engage the PTO. You can then ease the clutch out smoothly bringing the mower up to speed. Now bring the RPMs up to PTO speed. When disengaging the PTO depress the clutch first. That is the sequence told to my by my Kubota mechanic. It works for me.

Completely different PTO than your L2501. Gear drive L2501 is transmission driven, HST L2501 is live continuous. Where the M series is live independent PTO. My MX is also a live independent PTO, I wouldn’t call it “violent” it’s not smooth either. The clutch doesn’t affect it.

I usually don’t post much but I see this all the time on this forum, people jump in to help which is good but are completely off with advice and/or knowledge about the original posters model.

 

[NCL4701]

My L4701 HST has a “live independent” as well. No clutch at all so no feathering the PTO start like the older tractors I was used to. With the L, turn a knob and the magic of electricity engages a hydraulic clutch pack to start the PTO. If that hydraulic clutch had the same trainer I did (my father) it would engage more smoothly for fear of a boot in the butt and a sharp smack in the head. I have heard the electric over hydraulic PTO’s engage more smoothly if you already have the engine RPM’s up a bit, but I’m too much of a weenie to risk being hit by the potentially resulting shrapnel to try that myself so I’ve slowly gotten used to the “instant on” PTO, kind of like I’ve gotten used to the higher routine RPM of the modern Tier 4 v the old H that hit 540 on the PTO at 1650 engine RPM. I think it was @Henro who suggested the higher RPM thing.

I have noticed it’s a little less “instant” with the 200+lb flywheel on the WC68 than it is with the 5’ lightweight Howse bush hog so maybe that means something? Haven’t noticed any unusual wear on U-joints or anything else.

If you try it at higher RPM and don’t get perforated with remnants of what used to be PTO components, please report how that works out.

 

[cthomas]

May try just as the engine is cranking/starting engage the PTO? Try to time it at around 400 rpm's.

 

[Botamon]

If I just turn the PTO knob to "On" on my M7060 then yes, the engagement is harsh. I've learned to "feather" it by turning the PTO knob On and then Off immediately. That starts the PTO turning slowly. I do this once more, and the third time I leave the PTO knob On and its good to go. Each momentary engagement gets the implement turning just a bit faster.

 

[skipperbrown]

If I just turn the PTO knob to "On" on my M7060 then yes, the engagement is harsh. I've learned to "feather" it by turning the PTO knob On and then Off immediately. That starts the PTO turning slowly. I do this once more, and the third time I leave the PTO knob On and its good to go. Each momentary engagement gets the implement turning just a bit faster.

Tried this and I'm getting a much smoother engagement. Thanks for the tip.

 

[Borane4]

The PTO switch in an M4 is a simple electrical switch. Turning it slowly will not change the fact that its an on-or-off switch, It's the same as a light switch, the light is either on or off. That said, I never engage the mower (6' in my case) at anything higher than idle. It bucks a little as the blades swing out. Given the size and weight of the blades, the first rotations will go into the shaft and stump-jumper and the blades will initially fold in. Then as the shaft turns more, the blades will swing out and the whole cutter will smooth out. The bucking is inevitable with an on-or-off system. When you engage the PTO, there might be something mechanical that eases the PTO on, like a solenoid, but its pretty quick if there is.

 

[RBsingl]

Swing blade cutters are badly out of balance when they start to rotate and you are going to feel the imbalance as the blades move from folded to normal position.

IF your swing pivots aren't moving smoothly, very low RPM engagement will result in sustained roughness as one or both blades may be slow to swing out so make sure that they pivot freely.

As an experiment, level the cutter and stop the tractor engine. Manually swing out the blades and restart the tractor and engage the PTO and this will show whether the blade starting balance is the main cause of the roughness.

Rodger

 

[mcmxi]

The PTO switch in an M4 is a simple electrical switch. Turning it slowly will not change the fact that its an on-or-off switch, It's the same as a light switch, the light is either on or off.

If your post is in response to @Botamon then I think his point is that he's using the the PTO switch as a momentary switch to "pulse" the mass of all of the components that need to be accelerated. There's a lot of inertia to overcome, and typically the mass is not ideally distributed. Flail mowers are much smoother during initial engagement because the mass of the drum and hammers is much closer to being balanced at start up.

 

[JasonW]

Swing blade cutters are badly out of balance when they start to rotate and you are going to feel the imbalance as the blades move from folded to normal position.

IF your swing pivots aren't moving smoothly, very low RPM engagement will result in sustained roughness as one or both blades may be slow to swing out so make sure that they pivot freely.

As an experiment, level the cutter and stop the tractor engine. Manually swing out the blades and restart the tractor and engage the PTO and this will show whether the blade starting balance is the main cause of the roughness.

Rodger

Even when the blades are equal before starting the shaking is from the rotation of the stump jumper rotating before the blades catch up. The stump jumper will rotate making the blades pull back and hit the rear side of the blades on the stump jumper before inertia pulls them outward.

My MX has a live independent PTO but instead of a switch it’s cable operated, I am able to jog it on-off like posted above to help ease it up to speed at idle then raise engine speed.

 

[mcmxi]

Where the M series is live independent PTO. My MX is also a live independent PTO, I wouldn’t call it “violent” it’s not smooth either. The clutch doesn’t affect it.

I think the PTOs in my MX and M are independent rather than live independent. From what I've been reading, a "live PTO" uses a two-stage clutch which when depressed through the first stage disengages the transmission, and if the clutch is depressed more through the second stage it disengages the PTO. Independent PTOs are independent of the transmission and are controlled by a separate mechanical or hydraulically operated clutch to engage/disengage them.

 

[JasonW]

I think the PTOs in my MX and M are independent rather than live independent. From what I've been reading, a "live PTO" uses a two-stage clutch which when depressed through the first stage disengages the transmission, and if the clutch is depressed more through the second stage it disengages the PTO. Independent PTOs are independent of the transmission and are controlled by a separate mechanical or hydraulically operated clutch to engage/disengage them.

Both Kubota MX5100, MX6000, and M6060 brochures show the PTO as live independent

 

[JasonW]

Found this on another forum.

“Independent IS live, but live is NOT always independent. Live simply means the PTO keeps running when you disengage the wheel-drive.
With the Deere 1020, it's done with a two-stage engine-clutch.”

 

[mcmxi]

Found this on another forum.

“Independent IS live, but live is NOT always independent. Live simply means the PTO keeps running when you disengage the wheel-drive.
With the Deere 1020, it's done with a two-stage engine-clutch.”

Good to know. Thanks for sharing that.