1600 RPM vs. 1800 RPM

Wed Apr 17, 2013 10:07 am

What makes the difference between the two top end speeds? I have a '48 that has a tag at 1600. But I've seen tags of other '48s that are stamped 1800.

Is there something different internally to limit it to 1600? Was it just an "upgrade" by marketing?

And how do you turn it up?

Re: 1600 RPM vs. 1800 RPM

Wed Apr 17, 2013 10:45 am

On top of the governor is a small cap screw with a lock nut. Just loosen the lock nut and back the screw out a little. that allows the throttle lever to move further and give the higher rpm. That is the only change I know of at that point. Later ones that went to still higher rpm had different governor weights.

Re: 1600 RPM vs. 1800 RPM

Wed Apr 17, 2013 7:53 pm

I'm unclear as to where the 1600 stampings came from. The first production Cub (#501) was stamped 1800. Are you sure the 6 isn't just a poorly stamped 8?

The difference between the 1600 and 1800 figures is that 1800 was the maximum idle speed (no load). 1600 was the rated engine speed. Rated speed is the speed that it develops the most horsepower under a full load. Maximum idle speed is always higher then rated speed.