Work master 70 PTO Issue

[Nbastiani]

Hi all, I’m posting this for my father who has a NH work master 70 with about 200 hours on it. He hooked up the bush hog yesterday and started mowing. At 540 pto speed the engine is about 2200 rpm’s. As soon as it gets under load, the pto speed drops from 540 to about 100. Engine speed doesn’t change. He called the dealership and they said they’ve never heard of that happening. Any ideas? He just changed the gear oil in the bush hog. If I need to provide more info just ask. Thanks!

 

[RjCorazza]

If the tractor has a 2 stage clutch, it could be a simple clutch adjustment. I don't have a 2 stage clutch, but my understanding is that partial clutching disengages the pto, while full clutching allows for shifting.

 

[ROUSTABOUT]

If the tractor has a 2 stage clutch, it could be a simple clutch adjustment. I don't have a 2 stage clutch, but my understanding is that partial clutching disengages the pto, while full clutching allows for shifting.

Or he could be doing the cardinal sin and riding with his foot on the clutch.

 

[Jerry/MT]

Hi all, I’m posting this for my father who has a NH work master 70 with about 200 hours on it. He hooked up the bush hog yesterday and started mowing. At 540 pto speed the engine is about 2200 rpm’s. As soon as it gets under load, the pto speed drops from 540 to about 100. Engine speed doesn’t change. He called the dealership and they said they’ve never heard of that happening. Any ideas? He just changed the gear oil in the bush hog. If I need to provide more info just ask. Thanks!

I'd be surprised if it had a two-stage clutch. If it does, that could be the problem. Modern tractors generally have an independent pto which has a hydraulically actuated internal clutch mechanism in the pto drive line. If that is the case on this tractor, that's what is slipping and not fully transmitting the torque. The other possibility is if the hog has a slip clutch in its drive line and it is slipping.
If the dealership has "...never heard of that..." than they don't have much
tractor experience!

P.S. How did you determine the PTO speed was 100 rpm?

 

[Harry in Ky]

It DOES have a two stage clutch. And it doesn't operate with the clutch pedal. It has a hand operated lever that simply goes over center to engage the PTO portion of the clutch by pulling on a cable. That cable is the most likely source of problems. At least it has been on all the Workmasters I've seen. That is were I would start.

 

[Nbastiani]

Thank you all for the replies. He got the dealer to come out to show them what is happening, they said the problem is the pto clutch and they are picking it up tomorrow. Thanks again for all the info.

 

[Nbastiani]

BTW, Jerry/mt, the pto speed is on a digital read out separate from the engine rpm’s. That’s where he got the 100 rpm’s from. Thanks.