Finish Mower PTO Speed

[89 MJ]

I have a 1994 King Kutter finish mower that came with my Oliver 550. I know most implements run at either 540 or 1000 rpm, both of which I know how much throttle input that takes to get to on my tractor. My question is, what rpm should I be running a finish mower at? I know, this may seem like a silly question, but I have zero experience with equipment like this and I inherited the tractor and mower, and I intend to use them both.

 

[TractorDad3]

Hopefully there is a serial tag on the mower that lists the rated RPM, but it should be 540.
I run a 7’ finish mower off the back of my 550 that is 540 rpm

 

[89 MJ]

Hopefully there is a serial tag on the mower that lists the rated RPM, but it should be 540.
I run a 7’ finish mower off the back of my 550 that is 540 rpm

Thank you! I was thinking it should be 540, but I'll see what I can read on the tag. I've got a picture of it, but its been sitting outside for a long time.

 

[TomIn]

Most manufacturers of finish mowers suggest that the tractors be run at 540 rpm. This should give both a lot of power and a better cut because the tip of the mower blades will be moving near the maximum speed. This is most important if you are running the tractor in higher gears and/or when the grass is tall or wet. My finish mowing is mostly fairly rough reclaimed strip mining land and I mostly mow in 1st gear with my 1955 Ford 640 tractor. Being retired, I'm enjoying some seat time rather than trying to set a speed record. I mow at a lower rpm so that my butt touches the seat more often and the engine noise doesn't shatter my ear drums as much.

 

[89 MJ]

Most manufacturers of finish mowers suggest that the tractors be run at 540 rpm. This should give both a lot of power and a better cut because the tip of the mower blades will be moving near the maximum speed. This is most important if you are running the tractor in higher gears and/or when the grass is tall or wet. My finish mowing is mostly fairly rough reclaimed strip mining land and I mostly mow in 1st gear with my 1955 Ford 640 tractor. Being retired, I'm enjoying some seat time rather than trying to set a speed record. I mow at a lower rpm so that my butt touches the seat more often and the engine noise doesn't shatter my ear drums as much.

Sounds like you’ve got it figured out! Thank you for all of the information.

 

[300guy]

Looks to me like the mower is already hooked up to the tractor. So it doesn't matter what rpm it is, when you engage the pto it will run at whatever speed the tractor pto runs at. 540 pto is a course spline and the 1000 is a very fine spline. That's another way to see what speed your pto is.

 

[89 MJ]

Looks to me like the mower is already hooked up to the tractor. So it doesn't matter what rpm it is, when you engage the pto it will run at whatever speed the tractor pto runs at. 540 pto is a course spline and the 1000 is a very fine spline. That's another way to see what speed your pto is.

I did not know that with the splines. That’s not my tractor in the picture. I did know that it will run at the tractor’s rpms. I was trying to figure out the rated rpm.

 

[Aaron SEIA]

6 splines are 540, 21 are 1000. Unless it's for some compact utility that runs weird spline sizes, I'd bet it's 6 spline and 540 rpm.
AaronSEIA

 

[BarnyardEngineering]

I did not know that with the splines. That’s not my tractor in the picture. I did know that it will run at the tractor’s rpms. I was trying to figure out the rated rpm.

Industry-standard PTO implements are designed to run at either 540 or 1000 RPM, depending on the HP requirement for the implement. Lower HP implements like finish mowers are 540RPM, as evidenced by a 6-spline PTO coupler and the matching shaft sticking out of the tractor.

Old tractors lack a way of accurately measuring/controlling the PTO speed so it would make no sense to design your implement for, say, 319RPM. You can safely assume if it's attached to your Oliver 550, which only has a 540RPM PTO, that the mower is rated for 540RPM.

Your tachometer will have "PTO RPM 540" marked on it. As shown below that is 16(hundred) engine RPM. You want to maintain that engine RPM under load, so you need to start out with the RPMs higher before you put the mower in grass. Most likely you will be at wide open throttle to maintain 1600RPM while mowing.

It is not necessary to be "perfect." The mower will not fly apart if you run it at 541RPM unless it is in very poor condition, but then it would fly apart at 540 too.

 

[89 MJ]

Industry-standard PTO implements are designed to run at either 540 or 1000 RPM, depending on the HP requirement for the implement. Lower HP implements like finish mowers are 540RPM, as evidenced by a 6-spline PTO coupler and the matching shaft sticking out of the tractor.

Old tractors lack a way of accurately measuring/controlling the PTO speed so it would make no sense to design your implement for, say, 319RPM. You can safely assume if it's attached to your Oliver 550, which only has a 540RPM PTO, that the mower is rated for 540RPM.

Your tachometer will have "PTO RPM 540" marked on it. As shown below that is 16(hundred) engine RPM. You want to maintain that engine RPM under load, so you need to start out with the RPMs higher before you put the mower in grass. Most likely you will be at wide open throttle to maintain 1600RPM while mowing.

It is not necessary to be "perfect." The mower will not fly apart if you run it at 541RPM unless it is in very poor condition, but then it would fly apart at 540 too.
View attachment 69273

Good to know, thank you. Maybe it’s strange, but the 550s have the tach marked for both 540 and 1000 PTO rpm.

 

[89 MJ]

6 splines are 540, 21 are 1000. Unless it's for some compact utility that runs weird spline sizes, I'd bet it's 6 spline and 540 rpm.
AaronSEIA

I seem to recall it being 6 splines. Thank you.