Farmall M RPM

What is the easiest way to get a few more hundred RPM from the govenor? Is there an adjustment in the governor housing. What is the stock high RPM. I also am seeking a source for a Tach for the stock 6V postive ground system, is there such thing available?

Thanks in advance

Stiffer governor spring. I would not go past 1800 rpm if it has never been apart, or has not been apart in a long time. Parts loosen up over time, and you cant see to know. at 1800 rpm its a good difference to feel. Chad

They used to turn em to 1800 on generators a long time ago. High idle was 1980. Governor spring 57596D and governor spring fork 57597D. No idea if these parts atre still available. I got my M to 1800 by adjusting the governor high speed stop screw.

Full load RPM 1450. Don't know high-idle RPM. Some of you fellows out there who work with these things all the time probably can tell us.
In "my day" I used a little worm-drive "tachometer" with a rubber tip that you could put into the end of the PTO or in the center of the pulley. You had to calculate the ratio of PTO or pulley RPM to the engine speed.
Don't have M numbers here, but will use F-20 as example: Pulley speed 654 RPM at 1200 RPM full-load on engine. 1200 divided by 654 = 1.835.
If the pulley were running at 675, multiply 675 x 1.835 for engine RPM. You can divide the other way, too, to get pulley speed for a particular engine speed. The specs for these tractors often gave the "high idle rpm," which was easier to adjust than full-load because the only way to get full-load RPM with one of those primitive "tachometers" was to 1) stand next to the pulley while the tractor was operating a machine that provided a load, or 2) measure PTO speed while tractor was running something on the belt. I'm discounting walking behind the thing while it's plowing or something like that!
I don't know much about electronic tachs, but I assume that any one of those engine analyzers that hook up to a battery ignition system would give you an instant readout of RPM. I have a small one that I bought 30 years ago, when it was still possible to tune up your car, and I know that it was an easy hookup to get RPM while adjusting idle, carb idle mix, etc.

the factory high idle speed 1595. it is on the serial number tag.

I bought one from the TachShack the phone # is 952-881-7095