How can I improve the cut on my 21" Lawnboy?

Discussion in 'Mechanic and Repair' started by ealbertson, Feb 3, 2002.

  1. ealbertson

    ealbertson LawnSite Senior Member
    Posts: 256

    I have a Lawnboy Gold Series (aluminum deck) with a commercial grade 5.0 2 cycle engine. It cuts decently on thick grass but doesn't do well at all on tall thin stuff. When I say tall thin stuff I am not talking about a field. The one case is the first 21" of a small incline in a subdivision I do. It looks like it is just blowing the grass over. I am using the factory blade that came with it.

    Thanks for any help,

  2. Robert Doubrava

    Robert Doubrava LawnSite Senior Member
    Posts: 342

    Sharpen the blade if it needs sharpening, or get a new one?:confused: I'm really not sure, but the other guys oughtta know!:)
  3. Sounds like you are not getting good lift.
    1. like Robert said-sharp blade & not too worn?
    2. is underside of deck clean
    3. engine rpm's at high speed - too low?
    4. maybe try a high-lift blade if available

    That's all I came up with-are you trying to take too much off at once? Maybe cut high then drop deck for second pass for a cleaner job.

    BRIAN GALLO LawnSite Senior Member
    Posts: 282

    Make sure the engine is running at the proper rpm., Lawnboys have that wind vane governor and sometimes the spring looses some tension. It's adjustabe, however you will need to call your dealer to find out what the rpm setting should be, and you'll need a tachometer to set it right.
  5. vipermanz

    vipermanz LawnSite Bronze Member
    Posts: 1,773

    ED, are you using it with the mulch plate,side discharge or bag?

    also if you use Lawnboys' factory blades it won't be very good at all, the seem to all have a very low lift to them , i recommend a mulching blade that is serrated for the maximum perfomance.
  6. Jay NineteenLM

    Jay NineteenLM LawnSite Member
    Posts: 4

    Take the fan blade off from under the blade. It creates to much down force of air. I think lawn boy once called it a bagging assist blade.
  7. mowsho

    mowsho LawnSite Member
    Posts: 21

    Jay is right By taking the mulching fan off you will get a better cut in light grass. It was designed to blow the clippings out toward the ends of the blade not to discharge them. But by doing this they created another problem, it blows the weaker grass down and the blade misses it.

    This will solve your problem.

  8. Are you walking too fast??? This time of the year, when grass is growing fast, can't walk too fast. You'll get a lot of missed grass blades.
  9. landman

    landman LawnSite Member
    from NJ
    Posts: 110

    Just my opinion, junk it and buy a snapper.
  10. MOW ED

    MOW ED LawnSite Fanatic
    Posts: 5,028

    Are you using the blue smoke of death?

    I have a 21 LB with a 4.5hp and I rum AMSOIL 100:1 in it and it cuts pretty well unless it gets real long or is very wet. The Amsoil gives it more power and less plugging of the exhaust ports. I would drain the gas, take it apart at the bottom, clean the exhaust ports with a dowel, put a new plug in and refill the tank with the AMsoil 100:1 mix.
    The Lawn Boy oil is a petro based oil and it doesnt all burn up in the combustion chamber. It eventually gums the exhaust ports. The synthetic has superior lubricating qualities without a petroleum base, 95%less smoke and more power.
    Just my opinion as it works for me. Good Luck.

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