Mower Dies Unless Primer Bulb is Held.

Discussion in 'Mechanic and Repair' started by MowHouston, Sep 13, 2007.

  1. MowHouston

    MowHouston LawnSite Bronze Member
    Messages: 1,012

    I've got a 2007 21" walk behind that I haven't used in about two months. I drained out the old gas and put a little bit of new fuel in the tank but it still isn't working.

    The engine starts, runs erratically for a few seconds, then dies.

    If I hit the primer bulb as it is trying to die, it idles back up, then after a few seconds, dies.

    If I hold the primer bulb in, it stay running at a normal RPM.

    The engine is a Briggs & Stratton 650 Series 6.5HP for those who may have this mower and can help me.

    Any help is appreciated. I gotta try to get this mower going by tomorrow morning! Yikes. :)
  2. MowHouston

    MowHouston LawnSite Bronze Member
    Messages: 1,012

    Also: Even if I keep my finger over the hole in the primber bulb it works fine. I got some carb cleaner and sprayed the carb out but that didn't do anything.

    However, there is a little fuzzy gasket that fits between the air filter and the carb. It is torn. Might that have an effect on it?
  3. MuleCutter

    MuleCutter LawnSite Member
    Messages: 212

    make sure you have a good filter and it's not clogged. but my bet is that you need a new carb. for around $30-40 you can change it yourself. it's very simple. 3 screws to take the primer plate off and 2 bolts that hold the carb on. then disconnect the fuel line and reinstall the new carb.
  4. MowHouston

    MowHouston LawnSite Bronze Member
    Messages: 1,012

    I may try that. I've got it at an erratic idle right now. I sprayed carb cleaner at the carb while it was running now it is idling low with sparatic high revs. Think I should still go for a new carb?
  5. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Clean the holes in the bowl nut, This is also the main jet. Also replace this torn gasket.
  6. MowHouston

    MowHouston LawnSite Bronze Member
    Messages: 1,012

    Thanks a lot. I called my step dad to get some advice on that mower. He had me take off the carb, take it apart and spray out the jets. Its running fine now but I'm sure replacing that gasket is a good step too. I'll do that once I get the part.

    For those that have this problem: Leaving a mower to sit and not starting it during its dormancy allows the fuel to dry up in the carb and its jets. This makes a sort of varnish that will clog it up. Get some carb cleaner, take your carb apart and spray everything out until the cleaner runs through the jets clearly.

    I appreciate both of your advice. Thanks a lot for the help.
  7. Bill Kapaun

    Bill Kapaun LawnSite Senior Member
    Messages: 964

    That's why many of us use a fuel stabilizer such as STABIL.

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