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Power loss on hills

Discussion in 'Lawn Mowing' started by lahanko, Jun 1, 2002.

  1. lahanko

    lahanko LawnSite Member
    from NY
    Messages: 173

    I have a new Toro Z-Master 20 hp Kohler with 52-inch deck.
    The machine has approximately 20 hours on it and I have noticed a problem with it while going up steep hills (more than 25 degrees). The motor bogs down like it is about to stall (real close).

    The hill is in my back yard and I have gone up it many times with no problems. Today the machine was doing it every time I mowed up the hill. I tried the hill without the blades on and no problem, turned the blades on and tried the hill again, no problem, what gives? Runs great on the flat and once at the top of the hill where it levels out. The hill is about 60 feet to the top.

    Could it really be the plugs already? I did notice black smoke at one point when I just happen to look back.
  2. Tvov

    Tvov LawnSite Bronze Member
    from CT
    Messages: 1,157

    Possibly your choke is not adjusted correctly. You may have to have the dealer look at it.

    Also, with only 20 hours, you could have a dirty carb. Sometimes dirt or dust from the factory will get into a new engine and screw things up.

    For both these problems, carefully go over with the dealer what the warranty covers. Years ago I got screwed because the warranty didn't cover "dirty carbs" (I didn't want to mess with blower because it was so new), and I got stuck with a $40.00 repair bill for a new machine.

    Check to see that you don't have dirt/grass in the gas tank. The movement of the mower means that the dirt gets dislodged from the gas line inlet, but then eventually settles back down, causing problems. Also, if the dirt is not fully blocking the line, it will only make the engine bog when under load (like going up a hill), but not on flat ground. I had this problem last summer with one of my walk-behinds and it took forever to figure out what the problem was.

    Hope this helps.
  3. Mowingman

    Mowingman LawnSite Platinum Member
    from Texas
    Messages: 4,702

    I had a similar problem with a Toro ZMaster 23hp Kohler and 62" deck. I bought it last year and needed it for a 3000' long screening berm between a landfill and a road. The slope on this berm is so steep that the uphill front caster wheel on any of my ZTR's is constantly lifting of the ground as you work across the slope. The Toro could not be turned uphill without the engine bogging down and sometimes stalling out. My other mowers with 22hp or 25hp engines would go right up the slope. I lived with the problem for 200 hrs, then sold it and bought a Grasshopper midmount diesel. It goes up the hill with no trouble. I wondered if Toro had some oddball gear ratio in their hydro. motors or pumps?
    Maybe to get their speed up, they sacrificed power.:)
  4. Likestomow

    Likestomow LawnSite Senior Member
    Messages: 997

    Pull the left spark plug. If it's fouled, you have a blown head gasket.
  5. TLS

    TLS LawnSite Fanatic
    Messages: 7,943

    Fuel filter?

    Fuel line pinched?

    Something is preventing your carb from getting enough fuel. With it being new, have them check it out!

    The newer TORO/EXMARK Z's have rollover shutoff mercury switches. I'm pretty sure that these are a ON/OFF type switch. Either it runs, or it's over on its back!

    Let us know what it is!
  6. Albemarle Lawn

    Albemarle Lawn LawnSite Bronze Member
    Messages: 1,544

    Two of my Gravely 260Z mowers have this problem, both Kohler 25HP engines.

    I'm glad you started this thread because I was about to start the same thread.

    Mine will run well on hills only with the left hand side UPHILL (operator's left hand).

    If the right hand side is uphill, the mowers stutter and spit and lose a lot of power.

    (Sounds just like choke is on).

    The engines in the Gravely are mounted with the air filter to the rear of the mower.

    If the engine were mounted sideways, I suspect the problem would occur either going straight uphill or down.

  7. Albemarle Lawn

    Albemarle Lawn LawnSite Bronze Member
    Messages: 1,544

    Mine also give black smoke when they bog.
  8. awm

    awm LawnSite Gold Member
    Messages: 3,354

    if thats a command kohler,i have the same in exmark. it should pull any hill ,no problem . the black smoke of course would indicate carb problem. dealer adjustment should cover it.. .
  9. scottb

    scottb LawnSite Senior Member
    Messages: 408

    We are using a 25hp Kolher and it never bogs down. So like some have said take it to the dealer you need to have it checked out.
  10. Brickman

    Brickman LawnSite Bronze Member
    Messages: 1,249

    My Walker has the 25 Kohler. No problems with it. It will spin out, but nothing seems to wrong with the engine.

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