PTO RPM

[jdaugh]

Happy weekend, all. Nice weather.

I have a 1947 8N with no Proofmeter, obviously. I'm concerned I may be running my Rhino mower at too high (or too low) RPM. Is the only way to measure the PTO RPM to install a tach? Or is there a simpler way of estimating it? (My eyes aren't what they used to be, so counting the revolutions is out of the question. LOL)

Thanks for your help,

James
Abilene, TX

 

[Bruce (VA)]

Rule of thumb is 3/4 throttle gets you 540 PTO RPM. Or, you can do the math. PTO RPM = Engine RPM divided by 2.75. Max engine speed is supposed to be 2200 RPM. 3/4's of 2200 RPM is 1650 RPM. 1650 divided by 2.25 = 600 RPM. Close enough for government work.
50 Tips

 

[JMOR]

(quoted from post at 08:49:00 04/19/09) Happy weekend, all. Nice weather.

I have a 1947 8N with no Proofmeter, obviously. I'm concerned I may be running my Rhino mower at too high (or too low) RPM. Is the only way to measure the PTO RPM to install a tach? Or is there a simpler way of estimating it? (My eyes aren't what they used to be, so counting the revolutions is out of the question. LOL)

Thanks for your help,

James
Abilene, TX

Back in the days when these tractors were being manufactured, a farmer could buy, for a very few dollars, a mechanical counter with a rubber tip on it which he would push up against the center if the PTO shaft foe one minute and it registered thr number of revolutions in that minute. Such VEEDER-ROOT counters are no doubt still around, somewhere, but it isn't going to hurt your Rhino to over/under speed it by 50% anyway. So, just jump on and ride, ride, ride.

 

[souNdguy]

I agree with the others.. close is close.

you can also get a small engine inductive tach for about 50% that uses a spark plug line as a pickup and has a lil lcd readout.

soundguy

 

[Dell (WA)]

James......540-pto is NOT sacred, but 3/4-throttle will gitt'cha in the ballpark and close enuff.

Iff'n yer sphincterly challenged, you can gitt a watch battery powered LCD tach from yer local professional lawnmower-landscaper dealer (Northern Hydraulics and JC Whitney also sells) that are sticky-back applied to yer tractor dashpanel. Then you just wrap an insulated wire around enny sparkie wire and yer good to go. Only works in daylite. (frown) .......Dell

 

[jdaugh]

Thanks Dell. Inductive tach. Never thought of it. Only works by day? Me, too.

Cheap enough from Pep Boys I'm sure, but I'll use the 3/4 throttle advice. Sounds the most scientific. LOL

Thanks as always, ya'll!

 

[Anonymous-0]

Hmm. That's interesting. After Googling it and seeing what it looks like, we use something EXACTLY like that to count the revolutions of the flap-drive torque tubes on the C-5 Galaxy. Right where they enter the flap pack. (Make sure you're not wearing gloves when those babies are spinnin'!) That way, we can ensure indicated position matches actual flap position. (You can also select 100% flaps and count the revolutions to make sure they are extending fully to their stops.)

I'll take my tractor to work with me one day and check it out...

Thanks for the suggestion!