Bush hog blade stopping

[Unclewillie]

So explain why the PTO shaft is slowing down same as the blades....yet the engine RPMs don't?

I was in the belief that the tractor has no issues, therefore it's a problem with the rotary cutter. It's possible the hub that has the large bolt that the blades attach to has stripped out splines or shear key allowing the blades to turn until a certain amount of resistance then the blades hub simply spins a On the shaft.

 

[Unclewillie]

So explain why the PTO shaft is slowing down same as the blades....yet the engine RPMs don't?

I'm the case of pto shaft slowing same as the blades on an hst first thing I would do is clean the hydraulic fluid screen and filter, if that don't work i would worry if an electric clutch is involved.

 

[Midniteoyl]

What's so confusing to you about Unclewillie's post? Seems pretty clear to me. Some tractors have a key, usually on the hub for the one way clutch, on the PTO drive line inside the transmission. If it's sheared, the mower would stop spinning once it hit the grass and the engine RPMs wouldn't change. It might create enough drag to spin the mower in the up position.

Pretty sure he's talking about the rotary mower's gearbox.

 

[LD1]

What's so confusing to you about Unclewillie's post? Seems pretty clear to me. Some tractors have a key, usually on the hub for the one way clutch, on the PTO drive line inside the transmission. If it's sheared, the mower would stop spinning once it hit the grass and the engine RPMs wouldn't change. It might create enough drag to spin the mower in the up position.

He said a key on the gear in the gearbox. There is nothing wrong with the mower

 

[LD1]

I'm the case of pto shaft slowing same as the blades on an hst first thing I would do is clean the hydraulic fluid screen and filter, if that don't work i would worry if an electric clutch is involved.

Yes. It was later in the thread after several people were asking questions that he said he can physically see the pto shaft slowing down. He has a problem with the tractor

 

[Unclewillie]

Very sad anyone has tractor trouble, like a hurting friend.

 

[Williy]

Many moons ago I was chopping hay for a farmer
and his tractor was 100 hp IH and the chopper was IH also got into some really think alfalfa clover tractor started to snort then stopped dead. What happened was one of the hydraulic hoses broke and farmer took it in for repair instead of buying a new hose that would be long enough to replace the broken hose but no he just switched the hoses! bummer really jammed the chopper up!

willy

 

[marhar]

I was mowing grass with a 5 foot light duty King Kutter brush hog using a 40 horsepower NH tractor. It cut well in areas I had cut earlier this Spring but when it got into 2 foot tall grass (not that thick) it caused the blade to nearly stop but enough it did not cut at all. The mower has always been greased, the shear bolt was not damaged or broken. The blades are dull. When I would get back to the prior cut grass the blades would pick up speed and cut again but it had nothing for the taller grass. The tractor was moving at slow speed with engine RPM near 2500.
The problem is most of the grass is tall as my main tractor and mower have been down for 3 months waiting for an odd sized O ring. Really need to mow the tall stuff with what I have. Any thoughts or suggestions?

The king Kutter has a center piece that spins causing the blades move out. The nut that holds the center piece in place has a pin to keep the nut from coming off by accident. If this nut has loosened the gear box will turn but the blades are not being forced out because the center plate is not spinning.

If you have the tractor off and in gear with the PTO engaged you should not be able to turn the plate. The nut should be on tight. I have indicated the nut I am talking about.

 

[LD1]

The king Kutter has a center piece that spins causing the blades move out. The nut that holds the center piece in place has a pin to keep the nut from coming off by accident. If this nut has loosened the gear box will turn but the blades are not being forced out because the center plate is not spinning.

If you have the tractor off and in gear with the PTO engaged you should not be able to turn the plate. The nut should be on tight. I have indicated the nut I am talking about.


View attachment 702516

There is nothing wrong with his cutter

 

[yanmars]

It has a new hydraulic filter and fluid about 5 hours ago.