HELP - need to turn up Lawnboy RPM

Discussion in 'Mechanic and Repair' started by walkbehind48, Jul 10, 2001.

  1. walkbehind48

    walkbehind48 LawnSite Member
    Posts: 9

    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.

  2. khouse

    khouse LawnSite Bronze Member
    Posts: 1,465

    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.
  3. Turfer

    Turfer LawnSite Member
    Posts: 99

    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 !
  4. vipermanz

    vipermanz LawnSite Bronze Member
    Posts: 1,773

    i'll take a pic of my carb and see if it's the same
  5. Richard Martin

    Richard Martin LawnSite Fanatic
    Posts: 14,700

    The disk may also be black. Mine was and it worked great guys. Thanks for the tip.
  6. walkbehind48

    walkbehind48 LawnSite Member
    Posts: 9

    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.


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