poor running B & S 16 hp?

Discussion in 'Mechanic and Repair' started by Yetti, May 13, 2007.

  1. Yetti

    Yetti LawnSite Member
    Posts: 6

    howdy Guys, I am new around these parts and had a question about a mower I put together a while back. its a 16hp twin briggs on a MTD/Craftsman chassie. heres the problem, when I start it and run it its smooth at first and then acts like its not getting gas. I have torn down the carb and cleaned it and have pumped out the tank and refilled with fresh fuel a couple of times searching for what is wrong. I never have found the problem. if you guys have any ideas I could use the help at this point.
     
  2. Midwest Lawn Services

    Midwest Lawn Services LawnSite Member
    Posts: 211

    is this a vaguard?
     
  3. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024

  4. Bill Kapaun

    Bill Kapaun LawnSite Senior Member
    Posts: 915

    Plugged fuel cap vent?
    When it exhibits the symptoms, momentarily loosen the gas cap.
    Have you changed the fuel filter?
     
  5. Yetti

    Yetti LawnSite Member
    Posts: 6

    16hp 656cc model 402707

    and yes I have tried it with the fuel cap off. the fuel system flows fuel fine through the line. I am wondering if that style carb needs more fuel pressure from the pump? I am thinking it maybe sucking the float bowl dry. if I pull the choke shut I can keep it running but its difficult to tell where the problem is at.
     
  6. Bill Kapaun

    Bill Kapaun LawnSite Senior Member
    Posts: 915

    Inadequate valve lash could cause these symptoms.
     
  7. Yetti

    Yetti LawnSite Member
    Posts: 6

    so what course of action should I persue to correct bad valve lash? I didn't really plan on tearing it down.
     
  8. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024

    Don't go running to the valves just yet....


    When you cleaned the carb. did you take the fuel pump apart ?

    If so did you replace the diaphragm ?

    Did you get all three springs back in properly ?

    If you didn't take the fuel pump apart I feel thats where you need to go, You can get just a fuel pump rebuild kit.
    Make sure all three springs are installed per the diagram below, Put a dab of grease on the tabs for the small brass springs to hold them in place for assembly.


    [​IMG]
     
  9. Yetti

    Yetti LawnSite Member
    Posts: 6

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