"What is the speed these things should go?"

AS fast as you can walk comfortably and still cut the grass. Not all of them are fixed speed. Most that are walk too slow for able bodied men as they don't want them too fast for women and us old codgers. Some have the option of different size pulleys, drive rollers, or other drive components. LB and Toro have mowers that adjust their speed automatically to you pace. "Personal Pace" mowers. Snapper did have an adjustable speed self propelled walk behind mower, don't know if they still make that or not.

We have an older 3 speed gear shift Lawn Boy.

Walt Conner

I forgot include my mower. Just in case it would help. It is variable speed. Husqvarna 87521RS

Included the link.

Here is a link that might be useful: Husqvarna

Variable speed drives most always have an adjustable cable to set the free play to your liking, but if it's set right there's not much you can do to speed it up except to adjust the engine governor to produce the max. 'legal' RPM.
Variable Speed drives employ a constantly-slipping belt that is tightened by the control to go faster, so if the cable is not set right the belt may not get tight enough to produce max. ground speed. That's where I would start if you want it faster.

Maximum ground speed on modern RWD mowers seems to be around 4mph.

saxman1,

Thanks for the response. I removed the cover, and it looks like the belt is about as tight as it will go. My neighbor says it is faster than his, but not sure what is normal. His is front drive and mine is rear.

It goes 30 feet in about 7 sec. Not sure the MPH. Math is not my strong point.

Thnaks.

I went to the Husq website and the mower that seemed closest to yours was 3.3 MPH.

Your time/distance measurement may not be precise, but if it were, it would be 2.92 MPH. I would let it get broken in and check the engine speed in about a month. You could probably push it to 3400.