Run @ 540 PTO RPM or faster when cutting?

high engine speed and low ground speed.  match fwd speed to cutting to get good results at full throttle

     As a matter of fact, I can not think of any piece of equipment that would require the tractor to be run at full throttle for any amount of time, EXCEPT......MAYBE......If I was pulling a onr row cornpicker with a full wagon attached.....and, I was buried stuck, and, even then, I would unhook from the picker !!!

Coke-in-MN wrote: high engine speed and low ground speed.  match fwd speed to cutting to get good results at full throttle

Edited by Stan IL&TN - 09 Jul 2011 at 4:01pm

Air cooled engines depend on engine speed for cooling. Less than full throttle while mowing is not a good idea since you're reducing the airflow and increasing the engine load by lugging. The Kohler people specifically state run the engine at max rated speed for this reason.  I don't pull the throttle back to idle if I'm just hopping off to move a stick or the down spout pipe, just have to stop the deck due to the safety switches. If I'm going to be off for several minutes, I'll slow it down, otherwise no. As far as the tractor is concerned, I've always ran it at rated speed for the PTO. I used to help a neighbor at harvest dump trucks. He had this odd Agri-Power tractor that had a 2 speed PTO. He told me to run it on 1000 rpm for the auger instead of 540. I remember breaking the shear bolt once in a bunch of truck loads.

Edited by Brian Jasper co. Ia - 09 Jul 2011 at 4:15pm

       I'm back as I could not resist this conversation !!! We have 5 or 6 tractors, and, I can honestly say, that I have never run one of them PAST 2/3s throttle in my life. I can still hear the old man telling me as a kid "You ever run that throttle up there again, and, I will put the governor back on" And, Victoryallis, if you are taking a swipe at me, you had better reread what I typed !!!

Remember-  the PTO standard speed, is that which tractor AND implement manufacturers use to base their design calculations.  The OP wasn't referring to lawn equipment, he was referring to an agricultural PTO-driven rotary.

On my Bobcat commercial mower, the instructions are very explicit-  "Bring the throttle to 1/3 speed, pull up on PTO engagement knob.  Once blade starts, advance to full throttle". 

Kohler's operating manual for the my CV750: "Do not operate the engine with working loads for extended durations at less than 2/3 governed speed, as overheating will occur".

Running a 6 ft Ford or a 7' Mott mower behind my IH 460 I bring RPM up to a point where mower has a sound when cutting that says blades are all the way extended and not rattling against the reel. Sorry if this above what the tach says is 540 RPM but it is the sweet spot on mower and tractor , Is it full throttle ? Unsure but might be higher than 540.

 acombine is to run at 540 when combing not in the banyard  should run about 545-550 when empty no materiaif you run it faster it shake the s--- out of the shakers and sievesl  benn there done that we ran 2 all the time 60 & 66

the only times we ran full throttle with pto equipment was when using the forage chopper,the silo filler(blower) and the portable feed mill when grinding oats or grinding baled hay for piglet feed.all other we ran at pto speed, haybine, baler, manure spreader, only two things that I can recall running pto real slow was the forage wagons and the pto powered elevator.

Gerald J. wrote: I know from chopping iron pipes and trees with my dad's mower, that a boot, even steel toed, isn't going to save your foot from the modern mower, probably won't even slow it down as it mulches your toes.....  life with half a foot is not as handy as with all your toes.

You're absolutely correct, Gerald, in fact, if you're wearing steel toes and wind up with a foot under a walk-behind, it is more likely for you to lose your leg just above the knee, than just a portion of foot.

I was lucky-  I only lost half a foot, and you are correct that it is rather unhandy.  Not unliveable, but one wears out shoes incredibly fast, and the asymmetrical gait is hard on the lower back.  You wouldn't believe how often people ask me "Why weren't you wearing shoes"...

Yeah... they're that stupid.  I don't even try to argue- I ask them for their shoe, and when they say "Why?"  I tell 'em I'm gonna throw it on the ground, run a mower over it, and show 'em how tough that shoe is, compared to a 212mph machete.

The fact is, there is NO inherantly 'safe' way of doing most things... but I certainly WAS wearing shoes, and I still have that shoe... and unlike most rotary mower accidents, I didn't do anything glaringly wrong... nothing stupid, just slipped and went down.

My 9-year-old son and 7 year-old daughter have seen that shoe, and just to make it very, very obvious of what they're dealing with, I placed a rock  in the yard at a strategic point, and 4 layers of 5/8" OSB against a tree... then drove over that rock, sending it through all four layers... and out the other side. Rule is, when they hear a mower running, they move to the other side of the house, so the mower is never, ever in view.

The only 'safe' lawn mower, is goats and sheep... and they've got their dangers, too... but they're a whole lot better to eat than a Lawn-Boy.

I run the lawn mower wide open, baler on the 190 at 1,500 to 1,700 rpm (way below 540 PTO), the discbine to get best cut I run at rated speed on the 7050 which is 2,300 rpm and 540 PTO. I have more tractor than implement so I rarely exceed 1,900 engine RPM on the 7050 when doing tillage work. The 190 XT get run at rated speed for most tillage. I think is says in one of my 185 sales brochures to gear up and throttle back for best economy. I have a Case 1896 - 2096 brochure that I believe says the same thing. Pulling the same equipment you did before but with a little bigger tractor gives good economy and better reliability according to these brochures. Now I'll have to dig them out to see if I made myself a liar.

I had a brand new gearbox put in a bush hog. While it was being repaired my grandfather, without me knowing, put the AGCO-Allis  5670 PTO to 1000 rpm. The  Bush Hog was a 540 pto. Anyway, after about 4 hours of light brush hogging...gearbox failed. So I know first hand running the implement at a speed for which it was not designed will cause failure.

Gosh, I have a new Bush Hog Razorback and my operators manual says in plain english to operate it at 540rpm, so I guess that is what I will do, as I don't like to tear equipment up because I do not own a bank.

Just so I'm not confusing anybody, 540 rpm on my D17D is like 1650 engine rpm and is what I run my 160 mower at. The governor limits the engine to 2000 rpm max.

victoryallis wrote: it blows my mind hearing of people running wide open.  To my knowledge none of my tractors have been ran wide open while I have owned them.  Drive slower,  switch to a bigger tractor, or take the 15 minutes and switch the PTO over to 1000 rpms.  If you run wide open you have more money than brains.  One reply talked about picking corn and having to run wide open what where you using a garden tractor? I haven't picked much corn in my life (that why gleaner makes combines) but using anything from a D-12 to a 6080 and never went past 3/4 throttle.

You must have more money than brains as well since you can afford a tractor 50% bigger than your equipment requires.