Remove the air cleaner, look down the carb with the choke open and a light. With the engine off, slowly move the accelorator linkage, there should be a squirt of fuel, (not a dribble) a squirt of fuel splashing on the throttle plate as the linkage moves. If it don't squirt (like a toy squirt gun) you need to check the accelorator pump and the float level.
Timing will cause a hesetation (well it is realy more like a low power problem) but the most common problem is the accelorator pump.
