RPM questions (nothing in the manual)

   / RPM questions (nothing in the manual) #1  

ohbehave

Bronze Member
Joined
Sep 4, 2012
Messages
76
Location
Knoxville, tn
Tractor
Kubota L3200 (2012)
I've got a new L3200.

I keep the throttle at less than max RPM...but not sure if there are any rules of thumb on where to keep the RPMs while working.

Is it best to keep the RPMs at some distinct sweet spot regardless of what I'm doing? I don't have a good ear on this new machine...and it is my first diesel of any type... so I don't trust myself to detect the sound of "bogging" the engine.

(during break-in, I'm varying the RPMs quite a bit.... even when I jump off, I set the idle at different speeds... but this question pertains to the post-break-in phase)

I found nothing about proper RPMs in the manual.
 
   / RPM questions (nothing in the manual) #2  
It will come to you as you use it. You will notice things, such as excess smoke, louder engine noise etc. Things that arent there when the tractor is running in the "sweet spot". Probably around 2,000 - 2,200 rpm.
 
   / RPM questions (nothing in the manual) #3  
Is there maybe a tic mark on the tach to indicate PTO speed ?
 
   / RPM questions (nothing in the manual)
  • Thread Starter
#4  
There is something that says "540"....so I tend to keep it up around there especially if I'm going to put the tractor under any kind of load.

But, I am doing so on a hunch.... guessing that it's a good place to be.
 
   / RPM questions (nothing in the manual) #5  
There is something that says "540"....so I tend to keep it up around there especially if I'm going to put the tractor under any kind of load.

But, I am doing so on a hunch.... guessing that it's a good place to be.

I think that "540" indicates where the RPMs need to be to get the max. specified HP from the rear PTO...some tractors have multiple speed (rear) PTOs
 
   / RPM questions (nothing in the manual) #6  
I have a B7800HST. I generally tun it a minium of 2000. More often around 23-2400. If I'm using cutter or tiller, then I run it a full throttle.A few years ago, I had a customer that complained that his tractor didn't have any power. Come to find out, he was running it at around 18-1900 because he thought he might hurt the engine. I told him to open it up and run it at no less than 2400. He's never complained since.
 
   / RPM questions (nothing in the manual) #7  
My two cents,
Your engine is governed. You can't over rev it. The governor should maintain whatever rpm you pick or close to it until is is loaded to the point that the engine doesn't have enough torque to hold the rpm.
After break in, use it and set the RPM where you feel comfortable. And yes, you will limit power if you limit the RPM. These Kubota engines are actually pretty high revving for a diesel. Funny, I did a quick search and sure enough the engine rpm is not specified but typically engine power is given at full throttle.
 
   / RPM questions (nothing in the manual) #8  
If the tractor is delivering power, I run it wide open. Just driving around, about 2200. Engage
pTO's at 1600.
 
   / RPM questions (nothing in the manual) #9  
If it's a hydro I would listen to the transmission, they like higher speeds, but chose a speed where it feels and sounds happy.
My Ford 1720sss is a 12x12 and when doing loader work I set the throttle at 1300 ~1500 because the loader hydraulics respond best there. If I run 2000 or higher the loader actually slows a bit and I can hear the hydraulic pump whine increase.
Chose an rpm that suits the task, A PTO powered attachment that doesn't necessarily need to be run at 540. A PTO generator is one application where 540 rpm is mandatory.
Most others can be varied to achieve the desired result.
90cummins
 
   / RPM questions (nothing in the manual) #10  
If it's a hydro I would listen to the transmission, they like higher speeds, but chose a speed where it feels and sounds happy.
My Ford 1720sss is a 12x12 and when doing loader work I set the throttle at 1300 ~1500 because the loader hydraulics respond best there. If I run 2000 or higher the loader actually slows a bit and I can hear the hydraulic pump whine increase.
Chose an rpm that suits the task, A PTO powered attachment that doesn't necessarily need to be run at 540. A PTO generator is one application where 540 rpm is mandatory.
Most others can be varied to achieve the desired result.
90cummins

That's sounds like very odd performance. I know the faster i run the engine the faster my loader or log splitter cycles up to about 2300 rpm. I think some of the large tractors have pressure/flow compensation. I'm not sure if they uses a variable displacement pump on these models
 
 
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