International 785 at what engine rpm is PTO at 540 rpm?

[GR Gold]

I have a tractor that is not common stateside, and I have been unable to get a paper owners manual for it. It has a tach that does not have an indication on it where 540 pto rpm falls. I’m wanting to use it to cut my hay with a Vermeer TM800, and don’t want to guess. Anybody have this information as well as where I might come up with a manual? Also, from the serial number, can someone tell me the year? Thanks in advance for your replies!

 

[matthies]

Just buy a handheld tach and then you know for sure.

 

[JimB2]

Hi, from your tractors S/N, see info below.
Then next photo down from Nebraska Tractor test for 784, the 785 is just the next generation of the 784.
Major difference in engine was the high compression pistons to make better starting and less smoke also may have the newer Bosch VE injection pump versus the older VA version on the 84 series.
My brother has a 684 and we found that running at 2140 RPM for 540 PTO RPM, the PTO was running the machine too fast(never did check with a shaft Tach), the baler would miss an occasional bale and the forage harvester the corn head chains were going too fast. Machines appear to run properly around 1900 RPM on the tractor Tach but only our opinion.

784 Nebraska testing

 

[GR Gold]

Thank you JimB2!

 

[BarnyardEngineering]

Some real world advice, don't get hung up on exact PTO speed. It's not going to explode if you are running 539RPM or 541RPM. In fact 540RPM is the "CYA" recommendation from the manufacturer, and the machine is capable of handling quite a bit more. They just bear no responsibility if you're running it harder than 540 and it goes kaplooey on you (it won't unless it's severely neglected).

Listen and feel for the best RPM. You want it to sound "clean" and not lug the engine. I found that the best engine RPM to run my disc mower-conditioner was 2000, which is 150 below PTO speed on the tractor I was using (CaseIH 5220 Maxxum).

Also unless someone modified your tractor for pulling and it's turning 3000+, it was designed to run at wide open throttle, and pull down to PTO RPM under load, so even if you open it up and let it eat, your PTO is only maybe turning 580RPM no-load.