I have a 66 tri carb 442. To stop having to crank the engine 45 seconds after the car has sat for a couple of weeks, I installed a draw through electric pump to fill the carbs. The problem is, the pump will not fill the carbs no matter how long it runs. I know the pump is working fine. My car has a return line from the mechanical pump back to the tank. Is it possible that the gas is being pumped back into the tank through the return? I’m thinking about pinching off the return hose and trying the electric pump then. I can’t find anything in the service manual about the return or how it works. The manual says only AC cars have the return hose but my car is non AC and no one has messed with it. The return system is all original. Thanks.

 

When you activate the throttle one time after the car has been sitting do you see the accelerator pump squirt fuel into the intake manifold? Just use a screwdriver and you should be able to move the choke plate out of the way to see the accelerator pump shot.

 

No pump shot until I filled the bowl with a squirt bottle.

 

Sounds like your electric pump isn't pumping. The return port out of the mechanical pump has a restrictor orifice that significantly limits the amount of fuel that can flow back to the tank. This isn't your problem unless the output of the electric pump is so meager that it isn't any more than the limited bypass flow. If that's the case, get a better pump. And sorry for the obvious question, but you do have the electric pump hooked up in the right direction, correct? Try disconnecting the suction line going into the mechanical pump, run it into a can, and see how much comes out of the electric pump.

 

Yes the pump is hooked up correctly. The pump is a Facet cylindrical red top, 40 gph. I’m going to try pinching off the return hose and see if that helps. I’m not positive as I haven’t checked to see if the pump is actually working. That’s next. Thanks.

 

Yeah, just because the pump is making noise doesn't mean it's working. Like Joe said, disconnecting the input to the mechanical pump and putting that into a bucket to test the electric pump is your best step. Don't worry, it won't actually flow very much so you won't get gas everywhere as long as the hose is going into the bucket.
Most electric pumps have a very hard time priming themselves. That's why they have to be located at or near the bottom of the fuel tank. Once they have gas then the feed line usually stays full. If the gas can drain all the way back into the tank then the electric pump is exposed to air and they don't move air very well.
Mechanical pumps move air just as well as gas which is why they can prime themselves.

 

Found out it is the return line bypassing the electric pump and allowing the fuel to go back to the tank. Used a plastic hemostat to pinch off the return and it works well now.