Outdoor Power Equipment and Small Engines - primer bulb not sucking

On my homelite weed wacker the primer bulb would suck then blow it back in. Someone said it maybe the little check valves in it or something is plugged up. So how do I unplug this thing or clean out the check valves?

If it is the bulb you will have to replace it. Simple enuff to test it, remove the line from the carb to the bulb and press the bulb while holding your finger over the inlet you just removed the line from. This should suck and hold your finger. Do the same to the outlet of the primer, the line that returns to the tank. This side should blow when the bulb is pressed. If the bulb checks good then a restriction in the fuel system, filter lines or carb is likely the problem.

The bulb is brand new and built onto the carb. It has suction but not blowing out in the line back to tank so something muet be plugged.

When in the circuit and the bulb is pressed, when it expands does it draw fuel? Also if it is slow to expand, most likely a restriction in the carb, filter or supply line. Even with the bulb being attatched to the carb, it can still be changed seperately. The only thing I can think of that would plug the outlet side would be the bulb valve itself or the return line to the tank. Even so this should not keep the suction side from working nor the carb from getting fuel as long as the other side of the circuit (filter, line, carb) is not restricted.

The check valve(s) is under the bulb. It is either a round rubber disk, or two smaller vlaves in a yellowish-white plastic piece. Blowing them out and using spray carb cleaner sometimes works, other times, replacement is needed.