Newbie PTO and Brush Cutter operation

[DenmanBC]

Forum members,

Here in coastal BC the ground is now drying enough to allow me to get out on my new L3902 to start brush cutting down the tall grass, broom and vegetation. Since tractor purchase I have mostly been doing FEL and box blade work on dry areas, but now it is time to go into PTO mode. My tractor is HST and has an on/off switch for the PTO engagement.

My specific questions are:

1) My basic understanding is to always engage the PTO at lower than 540 PTO revs but not at idle. Once engaged then bring up to 540 PTO. Correct ?

2) What revs do you recommend starting the PTO with an attached RC1860 on the L3902? Same as above?

2) Should revs be brought down to same level before disengaging the PTO?

3) When I am mowing + need to raise cutter to go over stumps/rocks etc should I turn off the PTO briefly or leave blade spinning?

4) When I am driving between areas that need brush cutting I was planning on turning the PTO off. Is it ok to turn the PTO on/off fairly often? Do I need to stop the tractor and/or reduce revs every time I turn PTO on/off? How do experienced operators handle this?

I am looking for any other wisdom regarding PTO and brush cutter operation that you think will help
(and will be much appreciated).

Cheers

 

[TheOldHokie]

Forum members,

Here in coastal BC the ground is now drying enough to allow me to get out on my new L3902 to start brush cutting down the tall grass, broom and vegetation. Since tractor purchase I have mostly been doing FEL and box blade work on dry areas, but now it is time to go into PTO mode. My tractor is HST and has an on/off switch for the PTO engagement.

My specific questions are:

1) My basic understanding is to always engage the PTO at lower than 540 PTO revs but not at idle. Once engaged then bring up to 540 PTO. Correct ?

2) What revs do you recommend starting the PTO with an attached RC1860 on the L3902? Same as above?

2) Should revs be brought down to same level before disengaging the PTO?

3) When I am mowing + need to raise cutter to go over stumps/rocks etc should I turn off the PTO briefly or leave blade spinning?

4) When I am driving between areas that need brush cutting I was planning on turning the PTO off. Is it ok to turn the PTO on/off fairly often? Do I need to stop the tractor and/or reduce revs every time I turn PTO on/off? How do experienced operators handle this?

I am looking for any other wisdom regarding PTO and brush cutter operation that you think will help
(and will be much appreciated).

Cheers

RPM and frequency are not big issues - always use the clutch.

Dan

 

[JasonW]

RPM and frequency are not big issues - always use the clutch.

Dan

Do the 02’s even have a clutch? They moved the brakes to the left side.

 

[PHPaul]

In general, The Hokie's advice is (IMHO) correct, however...

I'm making a few assumptions as I'm not familiar with the 3902 so if I'm wrong someone will no doubt correct me.

I don't think you have a clutch being HST and you have a switch that is either on or off...no "easing" it into position so yes, lower the rpm when starting from a stopped implement, engage the PTO then bring the engine up to rated PTO speed.

A bush hog will have a LOT of inertia and when you turn the PTO off, it'll coast for quite a while assuming there's no PTO brake. Not sure if your tractor has one.

You can lift the mower to clear stumps and rocks without turning the PTO off. In fact, I'd recommend it. Saves wear and tear on the PTO clutch.

 

[JasonW]

OP’s questions. You can engage at idle as long as it doesn’t stall out. Or either just above idle.
You will get the best cut quality at 540PTO. Idle the engine all the way down to disengage.

I would avoid driving over stumps and lifting the mower, just go around them. Usually you can lift them all the way up and not bind the driveshaft.

 

[TheOldHokie]

In general, The Hokie's advice is (IMHO) correct, however...

I'm making a few assumptions as I'm not familiar with the 3902 so if I'm wrong someone will no doubt correct me.

I don't think you have a clutch being HST and you have a switch that is either on or off...no "easing" it into position so yes, lower the rpm when starting from a stopped implement, engage the PTO then bring the engine up to rated PTO speed.

A bush hog will have a LOT of inertia and when you turn the PTO off, it'll coast for quite a while assuming there's no PTO brake. Not sure if your tractor has one.

You can lift the mower to clear stumps and rocks without turning the PTO off. In fact, I'd recommend it. Saves wear and tear on the PTO clutch.

I stand corrected. They did away with the transmission clutch on the L02. I dont think I would like that.

Dan

 

[SDT]

In general, The Hokie's advice is (IMHO) correct, however...

I'm making a few assumptions as I'm not familiar with the 3902 so if I'm wrong someone will no doubt correct me.

I don't think you have a clutch being HST and you have a switch that is either on or off...no "easing" it into position so yes, lower the rpm when starting from a stopped implement, engage the PTO then bring the engine up to rated PTO speed.

A bush hog will have a LOT of inertia and when you turn the PTO off, it'll coast for quite a while assuming there's no PTO brake. Not sure if your tractor has one.

You can lift the mower to clear stumps and rocks without turning the PTO off. In fact, I'd recommend it. Saves wear and tear on the PTO clutch.

Not familiar with 3902 but it is always adviseable to return engine to idle before turning PTO off on any tractor with a PTO brake to avoid unnecessary wear of the PTO brake.

 

[NCL4701]

My L has the electric over hydraulic PTO and no clutch. When I first started using it, I thought it was weird because even though the electric push button is actuating a hydraulic clutch, it slams in pretty hard.

I’ve heard if you engage it at high engine RPM the hydraulic clutch will slip enough to not break anything, similar to an electric clutch on a lawnmower, but it hits so hard at low RPM I’ve never had the nerve to try it at high RPM for fear of being shotgunned by all the shrapnel that I can imagine resulting.

The way I use mine with every PTO implement I have is engage at idle. I’ve never had a problem with the engine stalling or coming close to stalling even with the bush hog in tall grass. After engaging then adjust to desired RPM.

Mine also has a PTO brake, as I suspect yours does. Disengaging an implement with a good bit of inertia (such as a mower/bush hog) at high RPM is, IMO, wearing on that brake a good bit more than disengaging at low RPM. I’ve never replaced the PTO brake on a L4701 or L3902. I prefer to not ever replace the PTO brake as it appears to be buried somewhere in the rear of the tractor; a place I prefer to remain unexplored. Based on that line of reasoning, I idle down before disengaging.

I’ve run tractors with mechanical PTO and clutch. I agree with others, if your machine has a clutch, use it to soft engage the PTO same as you would to start the machine in motion. If your machine, like mine, doesn’t have a clutch, I wouldn’t engage or disengage at high RPM, but maybe I’m just a hand wringing scaredy cat.

Personally, I don’t like not being able to feather a clutch to start the PTO, but I very much like the PTO speed and ground speed being unrelated.

 

[GrumpyFarmer]

Congratulations on your new equipment.

my recommendation before getting happy with the throttle would be:

1. If not already done so, read the manuals
2. Check all the service points (make sure nothing loose, zerks lubed / oil filled before use)
3. Measure and check the length of the PTO shaft
4. Be aware of how far rear cutter throws debris and keep loved ones away. (Be aware of this if turning and changing direction whether near road building or person/animal)

you can probably reverse number 2 and 3 but I would check both before getting happy with the throttle.

Good luck and congratulations! (We like pictures, just sayin’)

 

[TheOldHokie]

Personally, I don’t like not being able to feather a clutch to start the PTO, but I very much like the PTO speed and ground speed being unrelated.

You get slall of that on the L3301,/l3902 HST with the clutch.

Dan

 

[NCL4701]

You get slall of that on the L3301,/l3902 HST with the clutch.

Dan

Just out of curiosity, do you get splittable brakes on the left and treadle on the right or clutch on the left with both brakes and treadle on the right?

Edit: And I thought you said no clutch on the 02 (post #6)??

Just asking. I’m not familiar with the L3902 updates v L3901.

 

[DaveFromMi]

I have a L3901 and engage the brush cutter at ~1500 rpm.
To quickly reduce speed of blades, stop tractor, leave PTO engaged, throttle all the way down. When at idle speed, disengage the PTO.
I rarely if ever disengage the PTO while mowing until I am finished.

 

[airbiscuit]

Engage and disengage the PTO at the lowest RPMs possible.
I often leave the blades spinning when going to another area, unless it is over 1/4 mile away.

 

[DenmanBC]

RPM and frequency are not big issues - always use the clutch.

Dan

Thanks for advice but HST has no clutch.

 

[DenmanBC]

Congratulations on your new equipment.

my recommendation before getting happy with the throttle would be:

1. If not already done so, read the manuals
2. Check all the service points (make sure nothing loose, zerks lubed / oil filled before use)
3. Measure and check the length of the PTO shaft
4. Be aware of how far rear cutter throws debris and keep loved ones away. (Be aware of this if turning and changing direction whether near road building or person/animal)

you can probably reverse number 2 and 3 but I would check both before getting happy with the throttle.

Good luck and congratulations! (We like pictures, just sayin’)

Cheers. Thanks for the good advice, particularly the safety stuff.

 

[DenmanBC]

Just out of curiosity, do you get splittable brakes on the left and treadle on the right or clutch on the left with both brakes and treadle on the right?

Edit: And I thought you said no clutch on the 02 (post #6)??

Just asking. I’m not familiar with the L3902 updates v L3901.

Splittable brakes on left. Forward and reverse on right.

 

[DenmanBC]

I have a L3901 and engage the brush cutter at ~1500 rpm.
To quickly reduce speed of blades, stop tractor, leave PTO engaged, throttle all the way down. When at idle speed, disengage the PTO.
I rarely if ever disengage the PTO while mowing until I am finished.

Helpful advice. Thanks

 

[DenmanBC]

In general, The Hokie's advice is (IMHO) correct, however...

I'm making a few assumptions as I'm not familiar with the 3902 so if I'm wrong someone will no doubt correct me.

I don't think you have a clutch being HST and you have a switch that is either on or off...no "easing" it into position so yes, lower the rpm when starting from a stopped implement, engage the PTO then bring the engine up to rated PTO speed.

A bush hog will have a LOT of inertia and when you turn the PTO off, it'll coast for quite a while assuming there's no PTO brake. Not sure if your tractor has one.

You can lift the mower to clear stumps and rocks without turning the PTO off. In fact, I'd recommend it. Saves wear and tear on the PTO clutch.

Very helpful. Your assumptions are correct. No clutch on the 3902 HST and no PTO brake. Thanks so much.

 

[PHPaul]

Very helpful. Your assumptions are correct. No clutch on the 3902 HST and no PTO brake. Thanks so much.

You're welcome. As you're new to tractor work and bush hogging, I'll point out one other thing: A bush hog has VERY heavy blades (hence the amount of inertia) and WHEN, not if, it catches a small rock it will fling it a considerable distance. Be sure the area is clear of delicate objects like truck windows and especially people. DO NOT allow observers within say 50 yards.

 

[Russell King]

Other things for a new operator…

If you are not sure what is on the ground or under the vegetation it would be best to walk the area first to find and mark any obstacles or things you don’t want to mow down. Things like wire or rope will get picked up and wrap around the blades so quickly you won’t have a good day!

Make sure the slip clutch is adjusted correctly or that the shear pin is correct or you can damage the tractor.

Drive the tractor and mower around in an open area first to see how the mower swings around behind the tractor (assuming it is three point mounted). Realize how that large thing behind the tractor can swing out and hit things in tight turns therefore stopping the turning at the front of the tractor. So plan on making large sweeping turns instead of tight turns.

Don’t catch the fence on the tractor or mower by trying to get too close. You can spend a little time trimming or a lot or time repairing fence depending upon your ability to get close! Remember that the mower will swing into the fence if you turn quickly while you are close to the fence so again move away from the fence slowly then start turning.