On Fri, 8 Jul 2011 14:43:08 -0700 (PDT), PaulD
wrote:

I am helping a neighbor with his push mower. He has a 6.5 HP Briggs
and Stratton engine.
When I prime the engine with gas using the little button on the mower,
the engine starts up with no problem, but then quickly peters out. Is
this likely a carberator problem? or a fuel supply problem? Are there
any quick fixes that we can try.
I am willing to give him a hand, but I don't really want to get into
rebuilding his carb or something like that. I might be willing to
clean the fuel line. I didn't notice any fuel filter on this unit,
but I might not be looking at the right spot.
Thanks,
Paul
Most likely plugged fuel jets or water in the float bowl. The
carburetor will need to be cleaned - which in this case will LIKELY
require removaland dissassembly. You MIGHT get away with putting some
SeaFoam treatment in the gas, letting it sit for a while, and then
coaxing it to run with the primer until it finally draws gas through
the jets - but it is LIKELY a waste of time and effort (as well as
SeaFoam) in this case. If you can remove the float bowl and clean it
out, as well as the jet that is part of the "bolt", THEN running sea
foam through it when it starts and runs poorly will probably finish
the job and this is easier than disconnecting all the governor
linkages etc and getting everything back together properly if you are
not really familliar with the setup.

It almost definitely will NOT have a fuel filter - and it is almost
certainly a carburetor problem.