Stalling New Bad Boy

Discussion in 'Mechanic and Repair' started by jackmen, Aug 9, 2010.

  1. jackmen

    jackmen LawnSite Member
    Posts: 36

    I just purchased a a new bad boy lightning 60" with the 26 HP Kawasaki Liquid cooled. This thing is a true cutting machine, very impressed with it and its ability.

    I do have a a problem though. If I put the engine at half throttle (2600 RPM) and engage the blades, the engine dies, or if I start to pull forward or reverse at that rpm, the engine dies. This happens Hot or cold, doesn't make any difference. The engines sounds fine, and doesn't run rough. Also if it dies and its warm, I have to choke it to get it going.

    If I bring things up to full throttle everything is fine, (which is where i run it any way).

    Just wondering if any one else has this problem with a new mower. I just got rid of a 23 HP Kohler on a gravely and it ran fine at half throttle.

    Almost sounds like the carb is not getting enough fuel at everything except full throttle. Unfortunately the carb is not adjustable for the fuel mixture. Is this maybe part of emissions issues,that they have to run these engines so lean?

    Can any body help that has had a similar issue? I am located 100 miles from a dealer, I was hoping to avoid a trip to him.

    Jack Mentink

    Rolla, MO
  2. Grubrunner

    Grubrunner LawnSite Member
    Posts: 245

    Now I understand why you're engaing the PTO at half throttle [very astute actually] but just curious why you would pull-forward or reverse at half throttle with the PTO engaged...?
  3. jackmen

    jackmen LawnSite Member
    Posts: 36

    I often run at only half throttle for the first several minutes till the motor is fully warmed up.
  4. retrodog

    retrodog LawnSite Silver Member
    Posts: 2,421

    On all the 26hp LC's we sell, I tell them to put the engine to full throttle before engaging blades, very normal issue on nearly all. Check your throttle rpms at full stick, and make sure it is running atleast 3600 with the blades off. If not, on the back of the engine where the throttle cable goes in there is a plate with 2 10mm nuts on it, loosen 2 nuts and move the plate up. That will raise your throttle a little more, and then maybe you can engage at half stick. Also another trick, before you engage your blades, you might let the deck down a litte, that relieves extra stress on the belt.
  5. pugs

    pugs LawnSite Gold Member
    Posts: 3,022

    Is this when the engine is cold or warmed up? Does it still die at half throttle after the engine has been warmed up or run for a few hours?
  6. Jake4551

    Jake4551 LawnSite Member
    Posts: 111

    Need to start your deck at full throttle. Takes a lot to spool up that deck. I have used mowers that choke down at full throttle, with some movement, much less 1/2 throttle.
  7. bradseabridge

    bradseabridge LawnSite Senior Member
    Posts: 720

    did you even read the entire original post? All the answers to your questions are in the post.
  8. Grubrunner

    Grubrunner LawnSite Member
    Posts: 245


    Do you know the number one reason for snapped deck belts?

    Anyone [dealer/owner/operator] who's been in this business for any reasonable amount of time will tell you, you should NEVER engage the PTO at full throttle!

  9. Jake4551

    Jake4551 LawnSite Member
    Posts: 111

    Thats bull grubrunner. Never snapped a belt EVER! starting a deck at full throttle. In fact I have only worn a couple of belts out. Do you believe it is better to put the excess wear on the engine??
    Grasshopper 721D if moving forward will not engage the deck at half throttle without serious drag on the engine, and sometimes killing the engine. Also same problem with 25hp kohler JD 757. These are commerical mowers, lawn tractors are worse yet, especially if you are moving at all.
    I will have to check my Ferris manual, but JD's that I have had in the past state in the manual, written by the engineers to engage PTO at FULL throttle.
  10. Jake4551

    Jake4551 LawnSite Member
    Posts: 111

    I have a Z4 manual here, and it does state not to start it at full throttle, but does not recommend a particular position. I have 2 Wright manuals one says 3/4 and another full. All of my JD manuals say full throttle. Not sure about my Ferris manual, not here right now.
    So opinion on this seems to vary by manufacturer. However, I think a lot of people at 1/2 are bogging their engines down too much.
    SO some manufacturers do recommend full throttle starts.

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