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B&S 5 hp starts but dies quickly

Discussion in 'Mechanic and Repair' started by Brad Davis, May 14, 2004.

  1. Brad Davis

    Brad Davis LawnSite Member
    Posts: 13

    This mower was given to me 3 years ago and it has always seemed to run a little slow, ( self propelled), but it cut good and always ran smooth so I just used it. Anyway, I bent the throttle linkage on something and after I "straightened" it out, the engine ran like it was a 20 hp! I thought "great"! So I got about half my yard cut tonight and it acted like it ran out of gas. Now it will crank and run good for maybe 2 seconds and then die. I can pump the fuel primer and get it to run just a little longer than normal, but that is all. Any ideas?
  2. fixer67

    fixer67 LawnSite Silver Member
    Posts: 2,100

    I would do a leak-down test (Compression test)
  3. LynyrdSkynyrd

    LynyrdSkynyrd LawnSite Member
    Posts: 179

    Check the carb bowel for water.
    If it has water in the carb the engine will run until it uses the fuel down to the water level an stop.

    When you bent or "straightened" the throttle linkage. Your engine may now be over revving.
  4. locutus

    locutus LawnSite Bronze Member
    from NC
    Posts: 1,266

    In my experience, this is how a Briggs engine normally runs. So whats the problem?
  5. SER

    SER LawnSite Member
    Posts: 60

    SER Says:
    I had a similar problem. I thought it was the carburetor, but it was not. I was just laszy and didnt check the entire fuel system. It ended up being a broken manifold. Yes a broken manifold. on your engine you have a plastic tube where the carb opening goes. There is a rubber "O" ring in between. I moved this and it was very loose. I pulled it out and I noticed that the part was broken. This is not a very expensive part, under $10.00 I believe.
    I would check the entire fuel system, from the gas cap to the fuel lines and carb.
    Good luck.
  6. barnard

    barnard LawnSite Senior Member
    Posts: 618

    pull the bolt (which actually has the main jet in it out of the bottom of the carb. Blow off bowl area with compressed air first. have your blow gun handy. when you get the jet out . blow it out with air then put it back. Mower should run correctly now.
  7. agreif

    agreif LawnSite Member
    Posts: 3

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