Fuel pump sounds like a machine gun

[Pizzi348]

So I have a 1933 J2, and I went to start it the other day. Normally I here the fuel pump click, and slowly come to a stop after a few seconds. The other day for some reason, it clicks really fast and it doesn't stop. And I can smell fuel... I'm assuming it's still push fuel in as the clicking noise doesn't stop.

Any advice?

 

[DrEntropy]

How old is the fuel? Ethanol is a hateful additive, it'll cause a greenish funky build-up if there's any place it comes in contact with metal and atmosphere. I'd be thinking of opening up the pump to inspect and clean the "flutter valves" in the base.

Another less likely reason may be the supply line to the pump from the tank is allowing air to be sucked into it from a crack or dried hose connection. It will not necessarily leak fuel, but will allow air to be drawn into the line.

 

[David_DuBois]

The J2 should have a L type, low pressure pump mounted in the engine compartment. About the only thing that will cause the rapid running you describe would be an air leak between the tank and the pump as Dr E. suggests. The other thing would be no fuel in the tank (the ultimate air leak). If I remember correctly, the J series didn't have any fuel gauge or low fuel light, instead having two lines running from the tank to a two way valve that controls which line supplies fuel to the carburetors. One position of the valve selects the line attached to a stand pipe in the tank (normal position). Upon running out of fuel from the stand pipe, the valve is switched over to the auxiliary line that draws fuel from the bottom of the tank - this supplies another couple of gallons of fuel to get you to a filling station. Of course this arrangement has one major drawback - if you don't switch the valve back to the primary position, the next time you run out of fuel, the tank is actually empty because you were drawing fuel from the very bottom of the tank.
Cheers,

 

[Pizzi348]

Hi Dave,

Thanks for the reply. I went outside, and looked in the tank and it seems that I should have enough, but maybe it's low. So I switched the knob to reserve and the fast clicking stopped. But now it seems to click once every two or three seconds. Maybe I sucked some air for having the tank selector set to the main line instead of the reserve? Will it work it's way out? I haven't started the car yet.

Thanks!

 

[Pizzi348]

Seems like it's fine now. Question though, if I check my gas often enough, running on reserve is fine then, all the fuel gets pulled from the same tank, it's just a matter of the line position... so technically there's not a reserve fuel tank then?

I can't believe I made a post about running out of gas

 

[DrEntropy]

:lol:

Not to fret, Matt. Hard to judge level just lookin' thru that hole!

A pal kept a willow stick on-board, indexing it by gallon increments. Start where it poops out as the "E" and add a gallon at a time while notching the stick. Works a treat and is a great conversation piece! :wink:

 

[David_DuBois]

If you run with the selector in the reserve position, you will need to be diligent about checking the level of fuel in the tank as there will be no other indication of the level. A dip stick as Dr.E suggest is a good idea. If you make it from a strip of scrap walnut, the stick will darken significantly anytime it is wet, making it much easier to read than on a strip of light colored wood.
Cheers,