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Fuel pump issue


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First time posting. I recently bought a 72 wagon,(pics to come), and am unable to get in running. I've tried pretty much everything just short of putting in a electric fuel pump. I've replaced the mech fuel pump three times, removed the valve cover to check my offset, and lastly put all three FPs in a vice and they all manually work. SMH. Finally as I went to install my EFP, found a hole in the fuel line going from tank to metal line, decided to pull the tank and replace all the lines and see if  that'll work. Any other ideas as to what it might be? when FP is hooked up, I get gas wanting to feed the in port, but nothiing coming out the out port to the carb.(put a clear tube in a jar with no avail. Tank is not back in yet, So I'm hoping that might be the remedy.


Aloha Gordon

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There should be a 1/4" plastic spacer between pump and the head. That would be pump, gasket, spacer, gasket, head. Is the spacer there?


There is also an eccentric on the front of the cam sprocket that works the pump.  Is the eccentric there?


Is the pump connected backwards with the inlet hose on the outlet side?

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I live Mill creek area. I did find a hole in the fuel line, in the process of replacing all the hoses. Took tank out and cleaned it up painted it so it's ready for install. I did install the pump back wit spacer and gasket, So that asspect should be solid. And I REALLY want to stay away from installing a EFP. Mahalo for the info and feed back. Will lets you folks know the outcome.

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There still are thousands of Datsuns running around with a stock mechanical fuel pump.  Maybe even millions.


The mechanical fuel pump does not use the engine cam eccentric to pump fuel.  The cam eccentric just pulls back a spring, on the fuel pump diaphragm.   The pressure on the diaphragm is held back by the needle and seat.  Only when the engine need fuel, does the fuel pump move fuel.  Both are calibrated to work with each other.  Additionally, the mechanical fuel pump pumps more gas, if needed at higher RPMS.


An electric fuel pump just tries to supply as much fuel at idle, as it does when the engine is running 7,000 RPM, WOT.  It does not ever "back off".


Most importantly, if the engine stops and the key is still on, the mechanical fuel pump stops pumping fuel.   If you get into an accident, and you forget to turn the key off, you are not continuing to pump fuel.


I know you can add oil pressure switches, and fuses, and other safety items to an electric fuel pump, but never forget, parts left off a car cost nothing, and cause no service problems.


I have found the most reliable Datsun is a pretty much stock Datsun.

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elelctric pump?

Nothing wrong with them

Just most kids put the biggest mother fucker on there then wonder why there carbs flood out. you have to add a regulator. and find a 12volt switcable soure and not make it look like a hack splice into the igintion system with a wire that looks tacky running to it.



theres is a aircond wire under the fuse box that should be there, a blu one. one can use that as 12volt switcable


the cheap made in Mexico mechanical are not that bad also ans is pretty Moron proof to install and is already the low pressure pump

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