Ops manual says engine speed rpm 2,476 should be PTO speed rpm of 540, however dash only shows PTO speed of ~495 at ~2,500 engine rpm with 72" land pride rotary cutter attached. Is this normal? I would need to get close to 2,900 rpm to reach 540 pto speed and rated revol. for L4760 is 2,600. Thoughts?
L4760 Engine RPM and PTO RPM
- Thread starter gscott
- Start date
What I see at first is that different models of L4760 have different engine speeds for 540 rpm.
The GST and manual shift are 2,550 rpm for 540
The HST is 2,476 rpm for 5401 rpm.
The Intellipanel can be calibrated to make it work in different situations according to the WSM.
Likely your panel does not have the correct operational coefficient number programmed in.
My calculation using your numbers 540 rpm/495 rpm=1.0909.
you say 495 pto rpm at 2,500 engine rpm.
To get engine rpm for 540 pto rpm multiply 2,500 *1.0909=2,727 engine rpm so almost 170 rpm less than you thought.
I have not read up on inputting the proper pto coefficient into your machine. It may need the special Kubota software, maybe not.
Another example involves travelling speed coefficients which need to be calculated when different tires sizes are involved, based upon tire dimensions and input into the Intellipanel so the travel speed reads correctly.
Dave
The GST and manual shift are 2,550 rpm for 540
The HST is 2,476 rpm for 5401 rpm.
The Intellipanel can be calibrated to make it work in different situations according to the WSM.
Likely your panel does not have the correct operational coefficient number programmed in.
My calculation using your numbers 540 rpm/495 rpm=1.0909.
you say 495 pto rpm at 2,500 engine rpm.
To get engine rpm for 540 pto rpm multiply 2,500 *1.0909=2,727 engine rpm so almost 170 rpm less than you thought.
I have not read up on inputting the proper pto coefficient into your machine. It may need the special Kubota software, maybe not.
Another example involves travelling speed coefficients which need to be calculated when different tires sizes are involved, based upon tire dimensions and input into the Intellipanel so the travel speed reads correctly.
Dave
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I have the HST. I bet you are spot on. I have the assembly instructions that shows how to get into service inspect mode and make changes, but it does not list proper PTO coefficient. Thank you for the help! This gives me something to take back to dealer, as I did not get taken seriously when I initially asked why the PTO rpm looked too low given engine rpm...
Well...loaded the WSM and verified the PTO setting is correct, so its got to be something else. Lead service tech is supposed to come out to house this week or next to check some grinding sound/feel while driving across slopes, so I will have him look into it further.
Not that it helps you, but mine reads perfectly. However, when mowing, I often just set the throttle wide open to 2600RPM.
Setting the cruise control will also give you an exact RPM readout.
One other note is that a heavy brush hog will probably cause enough drag to drop your PTO RPM down slightly from what the book suggests.
Setting the cruise control will also give you an exact RPM readout.
One other note is that a heavy brush hog will probably cause enough drag to drop your PTO RPM down slightly from what the book suggests.
I have to resort to other means to ascertain if my PTO shaft speed actually corresponds to the has marks on the tach. Mine is all analog (older unit, no electronics and glad of that). I used a Stewart Warner contact style mechanical tachometer on the end of the PTO shaft while running to determine the actual revolutions. It's right on the bean BTW in 540 and 1000 rpm modes.
This helps so I know I should be seeing 540 with no load. My wide open throttle would be over 3,000 rpm---my rated rev is only 2,600 rpm--maybe my engine rpm tach is off?
The relationship between engine rpm and pto rpm does not vary with load on the pto. This relationship is designed into the tractor using gears. If the pto slows then the engine rpm must slow.
Dave
Dave
That's what I meant...meaning if you set your engine speed to what the book says, then engage your PTO and start mowing, your engine speed is going to drop a little because the added load will slow down the engine speed.
Your tachometer will show a higher scale (mine reads 3000 RPM) but with the throttle wide open it won't rev higher than 2600RPM.