Primer bulb-carb routing

Short line on primer bulb goes to the left side of the carb. The long side on the primer bulb goes to in the fuel tank as the return line.

There are 7 different types of the 1950 model (types 1 - 7) and it came with one of these 2 carbs Walbro or Zama. The carbs are different as are the fuel line connections for each one.
Although this video is for the promer bulb you can see the routing of the fuel lines.
http://www.ereplacementparts.com/article/4262/How_to_Replace_a_Primer_Bulb.html

You will have one line from the fuel tank connecting to primer bulb the 2nd line going to the carb. If you connect it backward it does not pump fuel into the carb.

Kelly
(FYI Types 1 - 5 all have the same fuel line routing.)

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.

The lines should be connected to push fuel into the carburetor. The output (overflow) of the carb is routed back into the tank. So, two lines in the tank, one is an overflow (return) and the other is the suction. On the primer one line from the tank and the other to the carb. Connect so as to "push" fuel into the carb when the primer bulb is pushed.

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!

Change out the primer bulb and the small gas lines going to carb and primer. One of these has a small crack to let air get by and this is how you get a flat primer bulb. Pick the kit up at lowes for $6-8.

Fuel routing:
Tank to carb (filter on free end in tank, replace annually)
Carb to primer (primer sucks fuel through carb)
Primer to tank (primer returns excess fuel to tank) HTH
Lou

I have a McCulloch 3200 chainsaw with a cracked primer bulb and all the fuel lines were gone. I cannot locate any information on routing these lines to the carb. I have a new primer bulb and 3/32x3/16" fuel line. Please help me solve this problem.

the large hose from the tank goes to the suction side of the primer bulb. The large line from the out put side of the bulb goes to the bottom inlet of the carb.
the small line goes from the top outlet tube on the carb back into the tank near the primer bulb.

Carb has 2 nipples. top nipple gets line with filter on it from tank, bottom nipple receives line from bulb other side of bulb returns to tank