Bush Hog Speed

[JT White]

When I bought my Yanmar, it came with the Howse Bush Hog and the gent told me to use it in #2 pto position, in second gear and at 2300 engine rpm's. I have followed that setting for the most part since day one. I don't know the PTO speeds of which there are four and if I run it in, say 3rd PTO and 3rd transmission gear at 2300 engine rpm's, will it destroy my bush hog gear's? I do 5 acres with several trees and would like to get it done a bit faster. Do I stay with the original settings? Thanks.

 

[oosik]

I'm not sure what you are referring to by - #2 PTO position or #3 PTO position. Most normally - your Bush Hog should be used with the PTO rotating at 540 rpm. Your Yamaha should - in some way - show you when the PTO is at that rpm. Either by a digital readout - or a hash mark on the rpm dial.

OR - your owners manual might indicate what rpm to run the engine at to achieve 540 PTO rpm.

Your tractor gearing will then determine the "speed of travel".

The pastures I mow have smooth and rough areas. Even in the smooth areas I rarely go over 4 mph. Higher speeds tend to take any joy out of the mowing. Things will happen plenty fast at the more manageable speeds.

 

[JT White]

I'm not sure what you are referring to by - #2 PTO position or #3 PTO position. Most normally - your Bush Hog should be used with the PTO rotating at 540 rpm. Your Yamaha should - in some way - show you when the PTO is at that rpm. Either by a digital readout - or a hash mark on the rpm dial.

OR - your owners manual might indicate what rpm to run the engine at to achieve 540 PTO rpm.

Your tractor gearing will then determine the "speed of travel".

The pastures I mow have smooth and rough areas. Even in the smooth areas I rarely go over 4 mph. Higher speeds tend to take any joy out of the mowing. Things will happen plenty fast at the more manageable speeds.

Thanks for the input. My PTO has four positions. #2 is the PTO position I run the Bush Hog in. I also run the tractor in second gear. My tractor is a YANMAR and I have no manual, nor does my engine tach tell me anything about PTO rpm. I wasn't sure of what the hogs speed could or should be. So I have run it in PTO 2 and transmission Second gear at 2300 rpm's.. I'll have to do more research.

 

[big bubba]

suggest posting this in Yanmar Equipment on the forum for your transmission/ pto speeds if you don't have a pto rpm.. as mentioned, 540 pto rpm is what you're after. also, if you're concerned about tearing up the gearbox, just check the g'box temp after a session. if it were stressed, you should be able to tell
24 posts in 11 yrs must be a record

 

[JT White]

Thanks I'll look into it, but I would have figured that most if not all Bush Hods would operate at roughly the same PTO speeds. Just trying to get a handle on it.

 

[seville009]

I run my bush hog a full rpms. I just adjust the tractor speed as necesssary - slower in thick stuff, faster in thin stuff.

 

[LS Tractor Owner]

Thanks I'll look into it, but I would have figured that most if not all Bush Hods would operate at roughly the same PTO speeds. Just trying to get a handle on it.

They do---- 540 PTO rpm. All tractors will reach this speed at different engine RPMs. For example: My little LS MT125 hit the 540 PTO rpm at 2930 engine rpm. My LS XG3025 hits the 540 PTO rpm at 2510 engine rpm. They are both 25 hp, one a Yanmar, the other a Mitsubishi engine.

As BigBubba stated, go to the Yanmar forum, ask for information on your MODEL of tractor.

 

[oosik]

Example - my Kubota M6040 hits 540 PTO rpm @ 2160 engine rpm. It's 62 engine hp.

 

[LD1]

Found this on another thread

4 SPEED PTO
PTO 1 540 @2200
PTO 2 1000 @2200
PTO 3 ENGINE SPEED
PTO4 OVERDRIVE

Seems Unless you have a 1000rpm bushhog, even running it in PTO speed 2 would be dangerous. Spinning a bushhog rated for 540 at 1000rpm is a recipe for disaster.

Seems them yanmars had some pretty high TOP speeds....lol

But If I were you I'd do two things...

1. figure out if the bushhog is a 540 or 1000rpm gearbox.

We can help you with that if you tell us the gearbox ratio and how wide the cutter is. To figure the gearbox ratio.....spin the pto ONE complete turn and see how many times the blade carrier turns. For a 5' cutter.....1.5:1 or 2:1 is pretty common for a 540 gearbox. Something around that ratio would give blade speeds of ~12700-16900fpm. And if thats what it is, and you are spinning it at 1000rpm pto....you are spinning the blades close to double that....which is NOT good.

2. Second thing to figure out is your actual PTO speed. Searching it has come up with some conflicting information so I cannot gaurentee the information I posted was correct. But for under $50 you can get a tachometer. Either contact or non-contact type. Run the tractor and see what your PTO speeds "actually" are.

https://www.amazon.com/Mengshen-Tachometer-Non-Contact-Rotation-Measurement/dp/B01CZFCZTQ/ref=asc_df_B01CZFCZTQ/?tag=hyprod-20&linkCode=df0&hvadid=260742848592&hvpos=&hvnetw=g&hvrand=15604926294491669276&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9015010&hvtargid=pla-430392893645&psc=1

 

[fidowanttobe]

I have a $10-15 non contact tachometer of eBay and am surprised how accurate and how many times it comes in useful.

 

[WM75Guy]

Many times the tach has a mark showing where RPMs generate 540 PTO speed. This one is the red mark.

 

[LD1]

Many times the tach has a mark showing where RPMs generate 540 PTO speed. This one is the red mark.

View attachment 759671

Yup....except his yanmar has 4 different speeds the PTO can run...

 

[2manyrocks]

The OP posted in the Yanmar section and there have been some specific replies from other Yanmar owners.

Mowing - PTO speeds

When I bought my Yanmar 2310 about 2015. It came with the Howse Bush Hog and the gent told me to use it in #2 PTO position, in second gear and at 2300 engine rpm's. I have followed that setting for the most part since day one. I don't know the PTO speeds of which there are four and if I run it...

www.tractorbynet.com

I'm a little surprised there isn't a decal on the tractor showing the PTO speeds, but it may have been painted over by now.

 

[psvfd]

From my Yanmar manual.

 

[LD1]

So did we ever figure out if the bushhog is 540 or 1000?

 

[cathy liebchen]

So did we ever figure out if the bushhog is 540 or 1000i

It’s going to be 540

 

[LD1]

It’s going to be 540

And you know this how?

 

[sandman2234]

And you know this how?

I was thinking the same thing!
In my world of limited association with 1000 rpm equipment, I was under the impression that 1000 rpm equipment came with a fine spline coupler, as opposed to what we normally see in 540 rpm use.
One thing the original poster needs to realize, is that the speed of the bush hog blades is not the controlling factor when it comes to how fast he can mow the 5 acres of property. The controlling factor is simply horsepower! If you increase the speed of the blades (not a good idea to overdrive a 540 gearbox) then you will suffer in the speed at which you can travel.
I have a slightly different setup that might shed some light on this statement. I have 3 sizes of bushhogs, 6, 8 and 15 footers and I mow the same field a lot. If I pay attention to the overlap cuts, and keep them to a minimum, the overall time it takes to mow this field remains roughly the same no matter which mower I use, provided all of them are running sharp blades and I pay attention to how much overlap I have on each pass. It takes a certain amount of horsepower to cut and if you aren't using all of your horsepower, then you can speed up the tractor one gear to cover more ground (increase mph). In most cases with fields that are smooth we usually have already done that without realizing it. If you are traveling too fast to be able to stay on the tractor without bouncing off the seat, then you need a wider bushhog. Speeding up the blades will help in thick grass, but you loose by decreasing ground speed. I have trouble staying on the seat when mowing with my 6 foot bushhog, as the 65 pto hp will let me travel pretty fast and still cut well.
David from jax

 

[2manyrocks]

On paper, it's always ground speed times cutting width.

In reality, ground speed is effectively limited by the degree of roughness of terrain and cutting width is effectively limited by available PTO HP relative to how much material is being cut.

 

[LD1]

I was thinking the same thing!
In my world of limited association with 1000 rpm equipment, I was under the impression that 1000 rpm equipment came with a fine spline coupler, as opposed to what we normally see in 540 rpm use.
One thing the original poster needs to realize, is that the speed of the bush hog blades is not the controlling factor when it comes to how fast he can mow the 5 acres of property. The controlling factor is simply horsepower! If you increase the speed of the blades (not a good idea to overdrive a 540 gearbox) then you will suffer in the speed at which you can travel.
I have a slightly different setup that might shed some light on this statement. I have 3 sizes of bushhogs, 6, 8 and 15 footers and I mow the same field a lot. If I pay attention to the overlap cuts, and keep them to a minimum, the overall time it takes to mow this field remains roughly the same no matter which mower I use, provided all of them are running sharp blades and I pay attention to how much overlap I have on each pass. It takes a certain amount of horsepower to cut and if you aren't using all of your horsepower, then you can speed up the tractor one gear to cover more ground (increase mph). In most cases with fields that are smooth we usually have already done that without realizing it. If you are traveling too fast to be able to stay on the tractor without bouncing off the seat, then you need a wider bushhog. Speeding up the blades will help in thick grass, but you loose by decreasing ground speed. I have trouble staying on the seat when mowing with my 6 foot bushhog, as the 65 pto hp will let me travel pretty fast and still cut well.
David from jax

Preach it. Its what I been saying all along