View Full Version : HELP - need to turn up Lawnboy RPM

07-10-2001, 07:57 AM
This past weekend I picked up a slightly used Lawnboy Silver Series 21" with a 2 cycle 4.5HP engine (traded in a broken down Yard Man 21" with a good running 5HP B&S + $55 for the reconditioned Lawnboy). The mower runs great and starts on first or second pull - I love the 2 stroke motor. My question is how do I raise the max RPM on this motor? I had read in past posts that there is a "white disk" on the motor that governs engine RPM??? I am not sure of the location of the disk.... Also, does anyone know what the difference between the 2 cycle 4.5 and 6.5 horsepower engines is??? I know the newest Lawnboys come with 6.5HP 2 cycle...any info or tips on getting the best performance out of this mower would be appreciated.


07-11-2001, 11:27 AM
There is an adjustment above the throttle shaft. It is a little hard to figure out at first but you'll get it. The older engines has the head cast with the cylinder. The newer 6.5's has a separate head and larger bore and different carb. The older engines has plenty of power and will respond nicely to the higher RPM of a governor adjustment.

07-11-2001, 06:04 PM
If you look at the back of your motor between the carb and the block, you will see a white plastic fin looking thing. On the bottom of the fin is a white disk. You can turn this disk either way. It will "click" as you turn it. I just raised my rpms on mine yesterday. I adjusted mine from the side that he muffler is on. It makes a huge difference !

07-12-2001, 04:00 AM
i'll take a pic of my carb and see if it's the same

Richard Martin
07-12-2001, 06:02 AM
The disk may also be black. Mine was and it worked great guys. Thanks for the tip.

07-12-2001, 07:09 AM
Thanks everyone for the helpful tips on turning up RPM. I love this 2 cycle mower - it is so much lighter & more pwerful than the Muraay 21" 5hp that it is replacing.