Originally Posted by teapot

I have a Sovereign Classic 35 lawnmower with a Briggs and Stratton
engine. While cutting the grass last week the engine started to
stutter and finally died on me. First thing I checked was the fuel and
oil levels which seemed to be ok, then the spark plug which was also
ok. Next thing checked was the air filter followed by making sure that
the fuel jet beneath it wasn't blocked. Again, all seemed to be in
order. Getting desperate, I decided to take off the cylinder head and
give both it and the valve seats a good clean up (which they sure
needed!). During the rebuild I made up a new head gasket using the old
one as a template. All this has achieved SFA. I suspect that the
fault is fuel supply related - possibly those two rather flimsy
looking springs under the air filter which operate the butterfly
valve.

Any advice or suggestions would be appreciated.