The carb and fuel line is now empty but if you are really fussy, it might start up on choke and run for a short while to get rid of any residual fuel or fumes. Just drain the tank, pump the primer until it is just sucking air, then drain the tank again. Remove the bulb from the engine and check it.

If it is hooked up backwards, it could either suck fuel out of the tank and flood the engine by forcing fuel through the carb, or depending where the tank fuel level is with respect to the primer return line, could seriously lean out the air/fuel mix.Ī side advantage of a primer is it makes it easy to drain all the fuel out of a saw. Small perforations on the rubber could inject enough air into the fuel system to make the suction too weak. You can easily find the suction port by hooking a short fuel line from a container of fuel to each port in turn and squeezing the bulb to see which one sucks. When replacing these things, it is important that the suction port of the primer be connected to the carb and the other one goes back to the tank. In operation, the bulb should be pressed until you can feel fuel being squished through it, then you know the fuel line and carb are full and the engine should start on full choke with a couple of pulls. The primer base has two check valves in it that keep fuel moving in one direction only, and the device is meant to suck fuel up the fuel line from the tank, fill the metering chamber in the carb and then dump any excess fuel back into the tank. On modern engines they do NOT inject fuel into the engine and they cannot flood the engine if they are pressed too many times.

causing this problem: the ignition module, fuel filter, fuel lines, primer bulb, and carburetor. There is a misconception of how these things work. Check out their websiteits really slick caltrimmer. Quite a few smaller saws and trimmers have a primer bulb that lets you get the thing running with fewer pulls after it has been unused for some time, however the bulbs seem to have a short lifetime (ethanol again?) and I have seen problems with their replacement.

Prmer bulb stihl check