On Tue, 5 May 2009 10:07:03 +0100, shazzbat wrote:

It's running rich. Almost certainly due to air inlet restriction at some
point.

Possibly but when my B&S exhibited the problem pretty much identical to
the OP's it's down to one of the little flap valves formed by the "gasket"
between the base of the carb and the fuel tank getting stuck into the hole
it is supposed to cover and block. So far I've managed to get it working
properly again by simply taking apart, flipping the flap out of the hole
and making sure the gasket is positioned with maximum overlay of this flap
and hole then putting back together.

Bear in mind of course that then it will run weak and may nheed the
choke.

If it has a choke...

--
Cheers
Dave.