Hi,

A neighbor brought over her Sears Eager1/Briggs Quantum mower with an unstable high rpm problem. At idle it will stay at a constant RPM, but at max rpm it hunts back and forth for the correct rpm. This engine has a mechanical govenor. I can stablize the RPM by holding the rod with my finger, so I doubt the problem is carb/ignition related.

Something as simple as a worn-out spring?

thanks for any help,
mark

yeah it just very well may be a worn out spring. ir you hold it and the rpm stays steady, the gov. and all sounds fine but when you let go it starts doing it again, it may be the spring has worn out.

Thanks for the input...I remembered to bring in the numbers today
Model 124702 Type 3121 Date 90031325

I went to the Briggs site and downloaded the parts list...

Anyone know how the governor works? Maybe oil off the slinger hits the flat on the crank and provides the movement? The parts list does not show the mating of the parts very clearly, but that is my best guess.

thanks
mark

somewhat, i'm not sure on a quantum, but basically it uses that spring to hold it steady.

Hi,

Well I replaced the govenor spring, same thing...RPM surges up and down at high rpm. I pulled the recoil shroud and cleaned up the area around the govenor shaft, removed and reinstalled the governor arm, no change. As a test, I removed several coils from the old spring and tried that, hoping the extra tension would help overcome the governor, the RPM has increased and now there are some RPM spots where the surging is barely noticeable. She is able to mow with it, but I'd like to fix it properly.

Anyone have an idea of my next step?

thanks for the help so far,
mark

most likely its out of adjustment since you changed the spring, the governor arm hooks to a hex like little rod coming out of the engine, try taking and advancing the governor arm a little on that. if it sounds like its running at too high of a rpm, cut it off and put the governor back and try taking another coil out of the spring. i've had to do this with my 5hp engine before on a go cart

sounds like a worn throttle shaft sucking air ,or it might be running too fast too much tension on the spring , or a dirty air filter , i would chech the throttle shaft first

The governor shaft is round, no indexing, no flats, etc, only a slotted tip at the top. I held the shaft fully counterclockwise and held the arm towards the carb when I reassembled it. Are there directions on how to adjust the gov arm on the shaft?

How does the gov work? Oil slinging at it?
The engine runs fine if I hold the gov rod steady, the RPM is stable and the engine sounds good.

thanks,
mark

well i have no idea on a quantum, i rarely even work on em, and never a governor on one. except once but long ago. only thing i can think of is what scrench said, (worn throttle shaft). or you could try taking another coil out of the spring out of the old one of course and see if that helps or the governor linkage is a little worn, but thats not likely since most pushmowers are hardly used.