"Dave Liquorice" wrote in
ll.co.uk:

But that sounds like fuel starvation. Is the breather hole in the tank
clear? Does it run with the cap loose? Is the fuel filter clear? Time
to dismantle inspect the tank/carb/gaskets. As it did run well before
do not be tempted to adjust any of the jets or poke anything through
orfices. Backwards washing with clean fuel or a gentle blast of
compressed air should clear any miniscule spots of gunk.

Dave,
Thanks... There is no breather hole in the fuel cap. Even with the cap
loose, it still dies out immediately after it fires up. I'm OK with
dismantling things if necessary, but where is the fuel filter located? Is
it easy to access?

Al