GB.. I would check the idle circuit, as it seems either reluctant to draw fuel as demand increases, or over choking at hot idle. As it has been standing for a while, a good chance that a carb clean and blow through of the jets would sort it, plus the addition of a cheap inline fuel filter. Back in the day we would put on a longer length of transparent fuel line, dipping down then up in a "U". Easy way to catch the bigger lumps of rust and sediment passing the (probably) non existent fuel tap gauze filters. After a while, when no more bits came from the tank we put it all back to normal. Easier to take off the long pipe and dump the crud, rather than taking off fuel taps and float chambers.
Swarfy.
