You have to figure if it is a fuel problem or something else
Pull the plugs, are they wet with fuel? If so, likely problem is spark related not fuel
If the plugs are dry spray the gas oil mix into carburetor throat while
pulling over (helps if you have someone pull while you spray) Although
frowned upon starting fluid or WD40 can be used...no lube in spray
If motor starts and runs then dies it indicates a fuel system problem
Which can be a clogged filter,fuel line or carburetor issue.
Funny as it seems sometimes fuel shut off is closed also check tank vent is open.
A weak magneto may deliver enough voltage to jump gap of spark plug
removed from cylinder BUT be unable to deliver the much higher voltage
needed to jump gap under cylinder compression.
If a motor has ignition, compression and carburetion it HAS to run. If one
or more of these are not right it will not. Mechanics earn their living by
figuring out which. Compression reflects condition of rings and cylinder
due to wear...mechanic will always check compression first to see if engine
has enough life left in it to justify a tune up...no point in putting new
shoes on a dead horse.