well if electricals are ok it seems to be starving for fuel with a full carb of fuel it should run more than 1.5 seconds for certain
you did install the fat gasket at the bottom of the carb….under the HS nozzle going up the carb
try spaying gas in the carb face see it runs longer to confirm fuel starvation from the carb body itself
if it runs recheck fuel delivery … clean all passages with a fine wire in case something is crudded solid air blow everything
make certain the choke plate opens up!
since it did run good a short while ago I would overall anything where fuel flows from the tank to the carb including the top chamber doesn’t take much to plug up all these small orifices …try bypassing the side filter for a test
Joining AOMCI has priviledges 🙂
