I ran my P61 out of fuel,it sped up abit then i turned it off . After refuleing its runnin the same ive cleand fuel tank filter had top off carb had little bit of dust/dirt in there new plug etc it still running the same stalls all the time even between blipping throttle, has to be restarted with choke etc all the time, Im not that keen on adjusting mixture screws What else could it be? Ive ran with fuel cap loose its the same??
Sounds like you may have got some grud in the carb.
You may have to remove the carb, disassemble and clean.
Check the fuel lines and make sure there are no cracks.
Replace the fuel filter also.
Lee