"Jon Elson" wrote in message
...
PrecisionmachinisT wrote:


"axolotl" wrote in message
...
The unit under test is a generator powered by an 8HP Briggs. I cleaned
the fuel tank, replaced the fuel lines and filter, and installed a
carburetor rebuild kit.

Engine starts and runs well for five or ten minutes, then stumbles and
stops. Starts up again with a single pull.

What should I be looking for?

Kevin Gallimore

Stuck or misadjusted float.
I don't believe these recent engines use floats. They have a bowl above
the fuel tank that has fuel pumped by a vaccum-operated diaphragm,
and the excess fuel spills over back into the tank.

My guess is the magneto has gone bad, and fails when hot. If
you restart immediately, how long does it run the 2nd time?
If it gets progressively worse, each restart runs shorter than
the last one, that is a good indication it may be the magneto.
If you let it sit for 5-10 minutes before restarting, then it
runs much longer?

I had this exact problem on a 5 Hp recent Briggs engine.
I put a magnetic-coupled timing light on it, and saw the spark
got weak while running, and then no spark (no timing light
flashes) when it died. A new magneto coil fixed it.



Depends on how old it is then I guess...I have a coleman generator and also
a lawnmower with B&S engines having float type carbs, indeed, both are
getting on in years.

The mower had a magneto went out on it a couple years ago...but in my case,
some days it simply would not put out any spark....