Mowing rpm

[SacandagaBrad]

Originally Posted by TCBoomer

Just to be clear, you DO run WOT for mowing? Which would equate to about 3K on my TC24DA I believe.

You've got me thinking - what is the engine displacement on your 24DA? Wondering if they put a different engine in the DA vs the D and bumped up the RPMs for HP. Mine is 1.131 Liters with a 77 mm bore and a 81 mm stroke, FWIW.

[TCBoomer]

Originally Posted by SacandagaBrad

Yeah, first page of my tractor manual in section 4, Specifications, says Maximum Speed: High Idle -2800 to 2850 RPM and Rated at 2600 RPM. Low idle is 1100 to 1200. I pull the throttle all the way for mowing, engine runs somewhere between 2650 and 2700. So I guess I meant that I'm governed more than 150 rpms below the high idle speed. Even pulled open with no load (high idle I guess?), it doesn't go quite to 2700, so maybe mine is just governed a little slow. Always been like that. This will only be my 5th season of mowing with it, always done a nice job!

My 540 rpm rear pto runs at 2503 rpm engine speed. I always have a little trouble getting that extra 3 rpms dialed in

Now I understand what your saying!
And after looking again, I found what your talking about. I must have glanced right over some of that info in the past. In the middle of the MMM manual, I found where it says run it at rated speed...hmmm, what do ya know In the tractor manual, I found the rated and high idle speeds listed. Same #'s as yours, so now we're on the same page

My first dealer told me to run the MMM at 540 on the TC21D, so I always did and when I bought the 24DA, I never bothered to ask. What threw me a curve was when you said you run WOT, or close to it. Yet my tractor manual says never exceed the 540 pto mark as that could cause an overspeed condition. I thought that meant the MMM could overspeed. Duh...now I know what it really means Thanks for the clarification. And to think all these years I've been running it slow.

I don't know how much difference the 100-150 rpm will make, but I'll know soon enough sometime in the next few days.

[TCBoomer]

Originally Posted by SacandagaBrad

You've got me thinking - what is the engine displacement on your 24DA? Wondering if they put a different engine in the DA vs the D and bumped up the RPMs for HP. Mine is 1.131 Liters with a 77 mm bore and a 81 mm stroke, FWIW.

Again...same #'s as yours. Yesterday, for the first time ever I might add!, I cranked it up WOT/no load. It reached all of 2850. I'm anxious to see how it cuts running at a higher speed. I'll see what 2600 does first. If I like what I see, maybe I'll even bump up to 2700.

I wonder if 12:30AM(right now ) is too early to go out and mow

[SacandagaBrad]

Originally Posted by TCBoomer

Yet my tractor manual says never exceed the 540 pto mark as that could cause an overspeed condition.

Yeah, I always read that as a CYA from NH since you could be running a range of rear implements from just as many manufacturers that might have very tight design speed limitations. Their just warning that your rear PTO will exceed 540.

As far as the engine speed itself, I think its governed conservatively for delivering max power while keeping it well within design specs for longevity. Especially on the low end with the slow idle speed set at 1100 rpms. I know a lot of older CUT owners - some of their machines idle at half that speed. I think part of the reason for the higher idle speed is to keep the oil pumping up to the top end especially when throttling down from a hard run and hot engine. Most of my loader work, grading, and snow plowing is done around 1800 rpms, just sounds right when I'm running it.

I don't know I just run it the way it was set up and never tinkered with any settings, follow the maintenance schedule, and run it like a tractor - does all I ever wanted!

Neighbor is getting a like-new used Kubota 7610 delivered today, some excitement on the road! Its not BLUE, but not everyone can have one!