Why isn't my mower cutting?

Discussion in 'Homeowner Assistance Forum' started by MrC, Jul 29, 2007.

  1. MrC

    MrC LawnSite Member
    from Jersey
    Messages: 189

    I have replaced and sharpened my blades (Craftsman 21" mower) and for some reason after making a pass I can see that it didn't cut everything I just went over. I have it set at 3.5 inches and I don't bag the clippings. Am I cutting to high? What am I doing wrong?
  2. STL Lawn

    STL Lawn LawnSite Member
    Messages: 8

    Not sure...have you tried lowering it and see if the cut is any better. The blade may not be balanced correctly which would result in an uneven cut.
  3. nmez21

    nmez21 LawnSite Senior Member
    Messages: 712

    The height sounds about right for your area. As long as you aren't hearing anything that might signal low engine rpm's then you might have an airflow problem. If you've got a lot of grass that has collected underneath the deck you may want to scrape it out. If that isn't the problem then you might want to try "pitching" the deck a little by lowering the front of the deck a notch or by raising the back wheels up a notch.
  4. LarryF

    LarryF LawnSite Bronze Member
    Messages: 1,181

    Or................the deck itself may not be level. Is it 3.5" all around? I presume you already checked to make sure the blade isn't installed upside down and that the bolt is tight enough so that the blade is turning with the spindle.
  5. MrC

    MrC LawnSite Member
    from Jersey
    Messages: 189

    It does cut better when I lower it, but I'm trying to maintain the 3.5" cut. The engine does not sound like it's struggling and tune it up every year.

    I balanced the blade with the plastic blade balancers that you get at Home Depot. I labeled the top and bottom of the blade before removing it to prevent improper install. I also tighten the bolt enough because I definitely didn't want it come off. The underside of the deck is clean.

    I'll check to see if it's 3.5" all around tomorrow and try pitching it in a couple days.

    Thanks for all the suggestions!!!
  6. steve45

    steve45 LawnSite Bronze Member
    Messages: 1,325

    I was going to guess that you had installed the blade upside down.

    If there are little fins behind the cutting portion of the blade, they should be on top.
  7. Capemay Eagle

    Capemay Eagle LawnSite Bronze Member
    Messages: 1,752

    Did you buy mulching blades by mistake?? I had a Craftsman years ago and mulching blades never cut right on the thing..
  8. MrC

    MrC LawnSite Member
    from Jersey
    Messages: 189

    I tried to Craftsman mowers. One has a mulching blade which was recommended by sears and the other is the original blade. Should I replace the blade with another brand/type?
  9. JTF40

    JTF40 LawnSite Senior Member
    Messages: 875

    I made that mistake - ONCE - 30 years ago. :hammerhead: :usflag:
  10. Capemay Eagle

    Capemay Eagle LawnSite Bronze Member
    Messages: 1,752

    Nope, It is just time to replace the Craftsman with a new Quick 36..lol

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