Discussion in '4-Stroke Engines' started by 4-banger, Oct 6, 2008.

  1. 4-banger

    4-banger New Member

    I have an old flathead 3 hp briggs and stratton engine and it runs fine for the first like 5-10 mins and then it will loose power and stall and it wont even fire over for a few hours. Any suggestions on what I can look at to see what is wrong.

  2. RdKryton

    RdKryton Active Member

    After it stalls and will not restart check to see if you have spark. If you don't it could be a heat issue with your ignition parts. If you still have spark you have to look for a fuel supply problem.
    Good luck
  3. 4-banger

    4-banger New Member

    It has spark and when it turns over it spits puffs of white smoke out but never fires over. I believe it is getting fuel as I just rebuilt the carb in attempt to solve the problem, but it didn't help.
  4. Alaskavan

    Alaskavan Guest

    Is the spark jumping good? I had a situation where after the engine warmed up, the spark would start jumping across the side of the plug. The problem fooled me for a while because I could hear the spark so I assumed the plug was okay. If it's not a fouling plug, I'd guess Jim is right. It's been years since I last took sandpaper to a magneto, but I don't recall it being that tough.
  5. ibdennyak

    ibdennyak Guest

    Sounds like a bad coil. Not that unusual since the gasoline formulation has changed. Apparently the engines runs hotter causing the coil to malfunction at a certain point. This has been a problem in my brothers lawn and garden shop on both 2 and 4 strokes.
  6. 4-banger

    4-banger New Member

    How can I test the mag. There is no coil on this engine because it has a mag right?
  7. Mountainman

    Mountainman Active Member

    just a guess here - but - I don't think it's gas (hotter) problem

    I think that they are making cheaper coils now days..

    in the old days they never thought about saving 5 cents and making worthless parts

    but -- very common today....

    just a thought from --

    ride that thing Mountainman
  8. smokie old bikes

    smokie old bikes New Member

    I had that problem with the same engine after switching carbs and still had it i found that the gas cap wasn,t drilled for vacum releaf on a new cap smokie
  9. darwin

    darwin Well-Known Member

    Is this an old brigs with points? Also check the shear pin.
  10. darwin

    darwin Well-Known Member

    4 year old thread, thanks smokie.:confused: