Series III Fuel shortage

[louie1]

Tried to start my 72 Series III but failed. Found zero fuel getting to carb. Cleaned fuel bowl and screen, used primer handle to try and fill bowl with no success. Added small amount of positive pressure to fuel tank and bowl filled and small amount of fuel reached the clear inline filter at the carb. Jumped for joy, but hit my head on raised hood. Tried the ignition, the engine sputtered, then just cranked. Never having used the fuel pump primer handle, should I feel some pressure as it's moved up and down?
It's the original fuel pump, to the best of my knowledge, and don't wish to waste money on a rebuild kit if I really need a new fuel pump to start with. Has anyone had this kind of experience, and how did you fix?

[singingcamel]

sounds like a bad diaphram, i would replace the fuel pump,rebuilding is not that difficult tho.
www.singingcamel.com

[louie1]

Thanks for your response. Not having a good understanding of this type of fuel pump, what concerned me was my ability, with a small amount of positive pressure, to push fuel all the way through the fuel pump to the inline filter at the carb. I would have thought that they would have some type of check valve so your not pushing fuel back into the tank as well as forward.
Thanks again.

[luckyjoe]

Do not cycle the hand priming lever too quickly, pump slowly. Pull the lever up and hold a few seconds, release and wait a few seconds, then repeat... If the pump internals are OK, you should hear the fuel start moving through the pump, then you'll see fuel in your clear filter. Do not expect the clear filter to *fill* with fuel - about 25-50% full is normal.

If this doesn't work (or you cannot fill the bowl) you may have a bad fuel pump, and air leak before the pump, a clogged pick-up screen/tube, etc...

Regards,

Tom P.

[scott]

i replace my pump and it still wouldn't pump enough for high rpms. some one suggest the problem might be a grove worn in the cam such that the arm doesn't travel enough. i added an electric and it solved my fuel hungry engine's problem. i also put a regulator between the two pumps to sovle a leak that developed at the sediment bowl.

[Leslie]

I'm not saying that you don't have a problem with your fuel pump, but.....


I had a similar problem, ended up discovering that the fuel pick-up tube was clogged with 30+ years of varnish/junk, almost like a putty in there, very little space for fuel to be drawn up through.... I used PB Blaster and a .223 bore-brush to clean out the tube, instant improvement.


FWIW....