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Wierd Problem from 6HP Quantum

Discussion in 'Mechanic and Repair' started by genesis215, May 16, 2008.

  1. genesis215

    genesis215 LawnSite Senior Member
    Posts: 795

    I've got a wierd problem from a brand new 6HP Briggs & Stratton quantum engine. It runs fine for five minutes, but then sputters and dies, and can't be restarted for about half an hour. I replaced the spark plug when it first happened, and that solved it for a couple hours of use. Then it did it again, I replaced the spark plug, and it did not fix the problem. What is happening? It is a brand new engine with less than 15 hours of use.
  2. Leaf Jockey

    Leaf Jockey LawnSite Senior Member
    Posts: 360

    If it were my problem I would try to determine if its an ignition problem(like a bad coil) or a fuel problem(like a tank that is not vented properly). Test for spark after it dies and won't start. This will give you an idea where to start looking for a cure.

  3. lawnspecialties

    lawnspecialties LawnSite Silver Member
    Posts: 2,513

    I know this sounds "off the wall" but I know of a similar problem caused by this. If it's not electrical, check inside your fuel tank for a sizeable piece of trash floating around.

    Sometimes it takes a while for the trash to get pulled up against the fuel line and blocking off the flow. After it sits off for a while, the trash releases and the engine will run again until it gets sucked again.
  4. kawasaki1

    kawasaki1 LawnSite Member
    Posts: 108

    check for spark as soon as it quits. no spark= bad coil usually.
  5. AmsoilPower

    AmsoilPower LawnSite Senior Member
    Posts: 938

    When it starts to act like it is going to die, quickly loosen the fuel cap to allow air into the tank. If it comes out of it you have a bad fuel cap. Try it with a full tank as it will require less run time to act up. If it does not help, then it will be the coil.
  6. fixer67

    fixer67 LawnSite Silver Member
    Posts: 2,100

    Sounds dumb but you say it is a new engine. Did you remove the blue shipping plug from the gas tank. I know it sounds crazy but I have seen more than a few plugs left it. The owner would remove the plug and fit the tank and then put the plug back thinking belonged there. It is for shipping only. The REMOVE AND DISCARD label is not alway on the blue plug.

  7. genesis215

    genesis215 LawnSite Senior Member
    Posts: 795

    That cap is not in there, I checked it today. I also ran it, and it did fine, and never died. But, it still has a very bad exhaust miss. It has had it ever since I first bought it. I wonder if the engine was defective from the factory.
  8. fixer67

    fixer67 LawnSite Silver Member
    Posts: 2,100

    If you think that then by all means take it to the shop for a repair under warranty ASAP
  9. Fisher40037

    Fisher40037 LawnSite Member
    Posts: 36

    Could be just water in the fuel, which is not warrantable. Post you engine's
    model numbers for any recommendations for a quick cure.


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