do you allways have to run tractor at full rpm for work?
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Bird
Rest in Peace
Of course I like tachometers on any car/truck/tractor, etc., but of course they don't all have one. My 1995 B7100 was one without a tach. Normally, PTO speed is a couple of hundred RPM less than WOT. And sure enough, both the dealer and a Kubota factory rep told me that PTO speed was just a little less than wide open. So I'd just push the throttle wide open, then pull it back barely enough to hear a sound change in the engine.
for best results when running WHAT ?
The mower ? I agree with that.
Is that all you use on it ?
Full throttle is often NOT a good idea with ground engaging attachments.
It is more than a little disappointing if the owner's manual doesn't make that point.
FSE
Bronze Member
I remember the first time I cut with my BX2660 60" MMM. It was new so I varied the RPM running between 1800 to 2300. I was very surprised at the mower cut at the low RPM. Gave a great cut and the engine never changed pitch. Cut better than my JD mower WOT. Now I may not have tough grass but it is pretty thick. When I planted my yard I put down 1000 lbs of Kentucky Tall 33 and 2 tons of lime and 1000lbs of 10-10-10. It came up pretty good. Not too many thin spots.
TripleR
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Yes, the owners manual has a chart on engine RPM's for your mid and rear PTO for your attachments which should also have information.
I would have to check my manual, but for the BX2660 for my 1000 MMM to get that speed, I have to run about 2950 engine and for the rear 540, about 3100 engine RPM's.
General Lee
Veteran Member
Ok, don't be to hard on me about this newbie question I'm about to ask. I don't have any pto driven implements......yet. I don't really understand the 540 pto rpm's. On my B3200 the tachometer has to be around 2500 for pto speed (if I'm understanding the manual correctly). I guess what I'm asking is how can I run 540 rpm's at the pto when the lowest rpm's the tractor idels at is 1000? Or the B3200's engine specs mean the engine has to be at 2500 in order to make the pto spin at a MINIMUM 540?
Bird
Rest in Peace
General Lee, because of the gearing that 2500 rpm is the engine speed that turns the PTO output shaft at 540 rpm. So, yes, you've got it right.
General Lee
Veteran Member
Cool, Thank you
Ken45101
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My Bush Hog manual states that running the cutter at less than 540 rpm will increase wear on the blade pivots.
I have a bunch of equipment (tractors, mini excavator, mower, skid steer, backhoe) and almost never run anything WOT. I prefer to stay 10-20% below max rpms. It's the way I was taught, always back off a little bit from full throttle. However, today's good designs are probably built to take it.
However, when looking at a new tractor, I did not like the fact that a MX5100 had to be run at WOT to make 540 pto. I elected for an M5040 which gives 540 at 80% of max rpms. It also gives me some reserve throttle.
Ken
I haven't seen the EXACT wording that you refer to, but it is sometimes the case that a tractor puts out it's maximum POWER at an engine speed different to it's maximum SPEED.
Some manufacturers might design for and recommend an engine speed that produces 540 at the PTO maximum torque, or maximum power.
A design choice.
