mechanical fuel pump fail?

[jerryt]

I have a Datsun 1600 in my model t. The fuel is fed by gravity. I have a mechanical fuel pump on my Datsun motor. My question is fuel keeps seeping past the fuel pump. A lot of gas seeped into the oil pan. So I took off the hose to the carb and placed it into a glass jar and within a few days the jar was full. On the fuel line I have a fuel shut off. But I was always led to believe that the needle and seat would prevent the fuel from leaking and flooding the oil pan. I guess anything can fail. Im thinking of getting another mechanical fuel pump to replace the rock auto special I have on it now. But can a mechanical pump fail?

Thanks

Jerry

[datzenmike]

The fuel pump has two one way valves and both allow fuel towards the carburetor so even a good pump could have fuel pushed through it. Now the pressure can't be that much. A column of water one foot high is 0.433 PSI and gas is a lot lighter than water. Just how high above the fuel pump is the gas tank? Normally the needle valve on the carburetor is not subject to any fuel pressure when the engine is not working.

 

You say there is a shut off on the car? Is this from the motel T? That would make sense as it's carburetor would also be in the same circumstances.

 

Why not just turn the valve to off when not using it???

[Ooph!]

On the passenger side firewall there is a sediment trap that should have a shutoff valve, drivers need to lift the hood to open and close the valve. On the original motor there was no pump just gravity fed.

The carburetor needle and seat probably need a cleaning or replacement.

 

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