LawnBoy Model 5126 won't start

Discussion in 'Mechanic and Repair' started by jasong, Jul 3, 2007.

  1. jasong

    jasong LawnSite Member
    Messages: 1

    Hi everyone,

    I have an older Lawnboy (model 5126) that will only start if I shoot a bit of lighter fluid/carb cleaner into the carb. Here is what I have tried:

    - Emptied the floatbowl and cleaned it
    - Removed the main jet and cleaned it with carb cleaner (it was pretty plugged)
    - cleaned the air filter
    - removed the fuel filter (very temporarily to ensure it wasn't plugged)

    I have taken the carb off a few times to work on it. Everytime I have done this the float bowl is full of gas so I know that gas is getting to the carb.

    I'm sure that I haven't adjusted the jet properly since I took it out to clean it. From my understanding the adjustment of the jet would not impact starting. It only kicks in at higher RMPs. Am I wrong?

    I also noted that the spring is broken on the "air vane". To be honest, I'm not sure what that spring does. Moving the air vane still opens/closes the butterfly valve in the carb. However, moving the throttle control does absolutely nothing because it is not connected to anything anymore.

    I ordered a spring for it but would this prevent the mower from starting?

    Thanks for all of your help.
  2. Roger

    Roger LawnSite Fanatic
    Messages: 5,940

    Yes. The spring keeps the throttle in the proper position for speed control. Without the spring, the engine has no control mechanism for engine speed.

    Be aware the throttle spring is very delicate. Take great care when installing so that it does not get stretched out of shape.
  3. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Messages: 2,248

    The spring you are referring to is the governor spring and if it is broken/inoperable, there is nothing to hold the throttle shaft is an open position and this will inhibit the starting process.


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