Primer bulb doesn't pump gas

The primer does not necessarily need to work for the unit to run. It does have a choke to aid cold starts. However it is a good indication of something wrong in the fuel system. A primer bulb that does not return to shape or does so slowly indicates a clogged screen in the carb. Check the fuel filter and fuel lines. Replace the fuel lines if they are stiff or discolored, rebuild the carb and replace primer bulb.

The primer should pull fuel out of the carb, into the bulb and dump it back to the tank, if the fuel filter in the tank is blocked, or the fuel hose is split no fuel will enter the carb, so the primer will not fill, replace the filter and the fuel hose.

I have no diagram but here are the instructions on how it goes.
The small diameter line out of fuel tank (has filter in-tank on end) connects directly to the side of the carburetor that has the fuel pump....that is the cover without the hole in it. Other larger diameter fuel line out of tank connects to the longer nipple on the external purge/primer bulb. The bulb "pulls" fresh fuel from the fuel tank to the carb and then out of the carb to itself, where it then "pushes" any air/old fuel back into the fuel tank. The remaining larger diameter fuel line in this setup goes from the metering chamber (has cover with writing on it and a vent-hole) side of the carburetor to the smaller nipple on the purge/primer bulb. Again, on the primer bulb, the longer nipple has a line going directly from it to the tank. This is the return line. The shorter nipple on the bub has a line from it going to the metering chamber side of the carb. If the purge/primer bulb is on top of the carb...small line from carb body to small hole in tank with filter. Larger diameter line goes from the bulb on the fuel pump side of the carb to the larger hole in the fuel tank where sometimes the line is held in place with a nylon nipple connector that keeps the line from pulling out of the tank. Otherwise, the line should enter the tank for about 1/2" or so.

Who connected these hoses? the normal routing for a machine with a primer is like this, the fuel hose from the tank with the filter on the end goes to the carb fuel inlet nozzel ( not to the primer ) nearest to the pump cover ( cover on carb held with one screw ) the pipe from the metering side of the carb connects to the shorter nozzel on the primer bulb ( suction side ), the longer nozzel on the primer ( pressure side ) connects to the pipe going back to the tank, just remember the primer pulls fuel from the carb,into the bulb, and pushes it back into the tank, it is not actually a primer it is a purge. because it is connected this way it is impossible to flood the engine no matter how many times the bulb is pressed.
Let me know if it starts and runs.

You either need a new primer bulb (leaking air) or you have the fuel lines routed wrong. Here is the correct fuel line routing just in case:
Small diameter line out of fuel tank (has filter in-tank on end) connects to the side of the carburetor that has the fuel pump....that is the cover without the hole in it. Other larger diameter fuel line out of tank connects to the longer nipple on the external purge/primer bulb. The bulb "pulls" fresh fuel from the fuel tank to the carb and then out of the carb to itself, where it then pushes any air/old fuel back into the fuel tank. The remaining larger diameter fuel line in this setup goes from the metering chamber (has cover with writing on it and a vent-hole) side of the carburetor to the smaller nipple on the purge/primer bulb. Again, on the primer bulb, the longer nipple has a line going directly from it to the tank. The shorter nipple on the bub has a line from it going to the metering chamber side of the carb.If the purge/primer bulb is on top of the carb...small line from carb body to small hole in tank with filter. Larger diameter line goes from the bulb on the fuel pump side of the carb to the larger hole in the fuel tank where the line is held in place with a nylon nipple connector that keeps the line from pulling out of the tank

You may be overfilling the tank somewhat so that expanding fuel (from engine heat) is being pushed out of the vent. Check the fuel filter for plugging and all of the fuel lines for any rot, splitting, or other damage. The primer bulb is supposed to pull fuel from the fuel filter, then through the carburetor and on to the primer which should push the excess back into the tank through another line. If the above does not allow the primer to pump fuel, then dismantle the carburetor, clean with carburetor spray cleaner, and rekit it. Go to: http://www.drystacked.com for a 12 page article on Walbro brand carburetors--theory and troubleshooting. This information applies to most brands of carburetor. Hope this gets you running!

There should not be a vent hose--it probably goes to a port on the primer bulb. Check the fuel filter for plugging and the condition of all fuel lines (they should be original rubber, not plastic replacements). Try priming the carburetor with the bulb pump--it should pull fuel into the bulb after several pushes. If nothing, check the condition of the primer bulb--it should be soft without cracks or holes.The primer is supposed to pull fuel from the tank's fuel filter, into the carburetor top section, pass into the lower section through the metering valve which is controlled by the diaphragm, then out to the input port of the primer and out the other primer port to return fuel to the tank. Go to: http://www.drystacked.com for an excellent 12 page article on theory and troubleshooting of Walbro carburetors. Hope this helps!

The hoses run through a hole into the gas tank, they are fitted with a filter inside the tank. Drain the tank, and manipulate the hose end to where you can grab it throught he filler hole, Remove the filter, run new gas lines into the tank and through the filler hole to replace the filter, reattach to the carburator. The primer bulb should have 4 small screws attaching it to the carburator. Remove the screws, place in new primer bulb, and you should be back to trimming asap.

primer bulb on weedeater will not return to normal or **** gas into it. new primer bulb. lines to tank have been repalce and can blow through them but primer bulb will not push air into tank

Hi

Priming the engine(put some gas in the sparkplug hole)..If.Start the engine.If only the gas from the cilinder is burned change the lines prom primer bulb.

best regards savumihai71