Most primer equipped carburetors use a diaphragm equipped with flapper valves in between the primer and carb. This allows fuel to be drawn through from the fuel source one way, then pushed through to the throat of the carb the other way. Most primer system failures are due to this diaphragm being torn, pinched shut, inflexible, etc.
The small line from the tank (with the fuel filter) goes to the top port of the carburetor. The large line from the fuel tank goes to the center port of the primer bulb. The other port of the primer bulb goes to the bottom port of the carburetor.
No gasoline is reaching the primer bulb.
I'm having the same problem with my Poulan chainsaw and weed eater. I think the line starts with the fuel filter in the tank and travels up to the primer bulb, out of the bulb into the carburetor, and out of the carburetor back to the tank. Whatever the size of line is that hooks to the fuel filter is what will hook to the primer bulb and then the carburetor. Then one more single line returns to the tank. I may not be correct on this, but there's not much information available. The diagram on Poulan's website does not show the routing of the fuel lines. that is right but to remove the main line you need to drain fuel and pull the line out from the fuel tank neck first because it has a connection that will not fit threw the hole in top. to replace it cut new line at a slaint and fir it threw from the top down into the fuel tank. then keep it long and pull out enough threw the fuel cap to put fitting back on it and fuel filter then pull it back threw and hook it to primer bubble. Not sure about your answer I have two different size fuel lines on mine. The larger line if I remember correctly runs from primer bulb to the right of fuel tank where the larger opening is located. The smaller line is where I am confused at shouldn't the smaller line from the fuel tank that has in tank filter attached run up to carburetor. then a smaller line from primer bulb to second fitting on carb. byrumjr the line starts with the fuel filter in the tank and travels up to the carburetor out of the carburetor into the primer bulb, out of the primer bulb back in the tank
byrumjr the line starts with the fuel filter in the tank and travels up to the carburetor out of the carburetor into the primer bulb, out of the primer bulb back in the tank raylago fuel line routing is as follows for all 2 cycle with primer ball external to the carb. remember the fuel is sucked into the carb, not puished or blown into the carb. the filtered line from the fuel tank goes to the "in" side of the carb. this is usually right next to the high speed adjustment screw on a walbro carb. the "out" line from the carb goes to the suction side of the primer ball, the output of the primer ball goes back to the return line in the fuel tank. if you have to run the choke and the carb high speed screw will not adjust properly, reverse the in and out lines to the carb.
Connection nearest bulb is return to tank.
There are two lines inside the tank. The short line with no fuel filter on the end of it goes to the inlet, (suction) side of the primer bulb. The long line inside the tank, with the filter on the end goes directly to the fitting on the side of the carburetor. The line, inside the air box from the outlet side of the primer goes to the remaining fuel line fitting on the carburetor. http://store.chainsawr.com/
There are two lines inside the tank. The short line with no fuel filter on the end of it goes to the inlet, (suction) side of the primer bulb. The long line inside the tank, with the filter on the end goes directly to the fitting on the side of the carburetor. The line, inside the air box from the outlet side of the primer goes to the remaining fuel line fitting on the carburetor. http://store.chainsawr.com/
There are two lines inside the tank. The short line with no fuel filter on the end of it goes to the inlet, (suction) side of the primer bulb. The long line inside the tank, with the filter on the end goes directly to the fitting on the side of the carburetor. The line, inside the air box from the outlet side of the primer goes to the remaining fuel line fitting on the carburetor. http://store.chainsawr.com/
long line with filter goes from gas tank into carb shorter line goes to (INLET) suction side of primer bulb 3rd line goes from OUTLET side of primer bulb to other carb fitting
You'll have a total of three fuel lines associated with this saw. The line, in the tank, with the fuel filter attached goes to the fuel pump side fitting of the carburetor. The line, in the tank, that is about only an inch or so in the tank is the return line and originates at the "out" nipple of the primer bulb. And the third and last line goes from the "in" nipple of the primer bulb to the carburetor fitting furthest away from the fuel pump side. Note that the fuel pump side of the carburetor is the side that integrates the throttle idle speed screw." That return fuel line is a booger if you don't have to replace the main fuel line. The orifice is hidden from view UNDER the hole for the main line. However, I got it replaced and the old McCulloch works fine again.
Make sure you have the lines wright the skiney line from in the tankgoes to the top nipple on the carb the over flow line goes to the long nipple on the primer bulb and the other line off the primer bulb goes to bottom nipple on carb
You either have a bad bulb or a bad fuel line between the bulb base and the gas tank. If there is the slightest hole or crack in the bulb it will not work. They are easy to replace.