L3901 PTO will not come up to speed

[TexasConsultant]

I have a Kubota L3901 HST and 72” Land Pride brush hog. Last week I was mowing (everything was working fine) and stopped for a few minutes. When I started back up, the PTO would not come up to full speed. With the tractor at 540 RPM, the PTO is not spinning fast enough to cut.

Any ideas? Of course the dealership wants to immediately jump to replacing the PTO clutch ($$$$) but the tractor has very low hours. Hard to believe that is the issue.

Would appreciate any ideas or thoughts on where I should look for an answer.

 

[MapleLeafFarmer]

shear bolt or slip clutch on the mower depending how your mower is built maybe needs replacement or adjustment? something jammed in the belt area.?

with tractor off spin the mower blades while someone tries to hold the pto shaft stationary. if blades or pulleys turn and pto shaft can be held not turning then i would be looking at mower shear bolts or slip clutch out of adjustment.

or if mower blades belt driven is belt tension correct and not jammed by a stick or something like that between belt and pulleys/body of mower? belt jumped a pulley or tensioner?

i dont own that mower but would be looking in those areas first.

 

[Pawnee]

You said tractor at 540RPM. You meant tach at the 540 mark right, which is a lot more than tractor 540RPM.

You could verify that the PTO engagement mechanism is working properly.

Also, some implements have a clutch instead of a shear bolt. That could be out of adjustment and slipping.

 

[TexasConsultant]

You said tractor at 540RPM. You meant tach at the 540 mark right, which is a lot more than tractor 540RPM.

You could verify that the PTO engagement mechanism is working properly.

Also, some implements have a clutch instead of a shear bolt. That could be out of adjustment and slipping.

Yes, tach at the 540 mark. No slip clutch on mower. Appears the PTO is turning slow.

 

[TheOldHokie]

Yes, tach at the 540 mark

Is the PTO itself turning slow or are the mower blades running slow?

Dan

 

[TexasConsultant]

shear bolt or slip clutch on the mower depending how your mower is built maybe needs replacement or adjustment? something jammed in the belt area.?

with tractor off spin the mower blades while someone tries to hold the pto shaft stationary. if blades or pulleys turn and pto shaft can be held not turning then i would be looking at mower shear bolts or slip clutch out of adjustment.

or if mower blades belt driven is belt tension correct and not jammed by a stick or something like that between belt and pulleys/body of mower? belt jumped a pulley or tensioner?

i dont own that mower but would be looking in those areas first.

No slip clutch on the mower. Shear bolts are fine and no belts. I was mowing grass in the middle of the pasture. Did not hit anything, just stopped for a moment and when I restarted the PTO would not come up to speed.

 

[TexasConsultant]

Is the PTO itself turning slow or are the mower blades running slow?

Dan

the PTO is turning slow

 

[TexasConsultant]

Is the PTO itself turning slow or are the mower blades running slow?

Dan

PTO appears to be turning slow

 

[TheOldHokie]

PTO appears to be turning slow

Have you disconnected the implement PTO shaft and looked at the tractor PTO shaft itself?

Dan

 

[TexasConsultant]

Have you disconnected the implement PTO shaft and looked at the tractor PTO shaft itself?

Dan

Yes, everything appears normal. Hydraulic fluid is full, clean, and there are no apparent leaks. Tractor is kept in a barn and there are no oil spots on the floor.

I was mowing grass in the middle of the pasture. Did not hit anything, just stopped for a moment and when I restarted the PTO would not come up to speed.

 

[TheOldHokie]

Yes, everything appears normal. Hydraulic fluid is full, clean, and there are no apparent leaks. Tractor is kept in a barn and there are no oil spots on the floor.

I was mowing grass in the middle of the pasture. Did not hit anything, just stopped for a moment and when I restarted the PTO would not come up to speed.

Start by checking the PTO lever linkage. The PTO on a L3901HST is 100% mechanical and no "clutch" as most people understand that term. If its broken internally its a substantial expense in both time and money.. i posted the parts diagram for the linkage below.

Dan

 

[Ridger]

You said everything worked fine last week when using the mower. Just curious, what was your engine speed (tach rpm) when it was working fine? I have an L3940 and I have to run my engine speed at 2640 rpm to get 540 pto rpm.

 

[TheOldHokie]

 

[Russell King]

Look underneath the mower to see if something is all wrapped around the blades or around the shaft coming down out of the gearbox.

Be sure that you put some wooden or steel supports underneath the deck before you go underneath it.

 

[NCL4701]

If you have any other PTO implements, I would take off the mower and try it with a different implement. That would completely eliminate any possible issues with the mower being involved.

 

[TheOldHokie]

If you have any other PTO implements, I would take off the mower and try it with a different implement. That would completely eliminate any possible issues with the mower being involved.

Exactly!!

Dan