Hello again, I'm back to pester you all with more questions.
After my exhaust debacle, I'm still trying to figure out why I'm losing fuel pressure over time. First of all, the car is a '73 converted to dual Webers with rotary fuel pump mounted just below the battery. Initially I had installed the tank without a strainer, which I recently replaced. While out, I cleaned the tank well, and inspected all lines - no blockages. The line at the tank is not kinked either and the fuel filter before the pump is brand new. The pump is definitely working and getting voltage and its brand new. Kevin (rhodyguy) allowed me to borrow a fuel pressure gauge for the time being and I have verified that I get exactly 3.5 PSI at first startup and idle. Then, with a couple drives around the block, the PSI drops to almost zero, the clear fuel filer after the pump is almost dry and the car stumbles on acceleration. The tank is vented properly with a vaccuumline that runs out under the drivers side of the car.

When I first got the car it had a Facet style pump, but it was mounted very low on the firewall, almost parallel with the line. Maybe moving it higher like this and combined with being a "pull" rather than a "push" setup is causing the pump to starve?

Out of gas?

Ha ha, I could not resist!

Fuel pump is overheating due to working too hard?

Get a carter rotary and put it below the tank.

I can send the one from my blue car to you.

Joe just put on the FI pump.

John

John, you're the best! This is a carter, so I don't think its the pump but thank you for the offer. However, it might be overheating, it was pretty hot to the touch even though the engine was relatively cool. I think I'll try to move it to the front. The PO already cut a hole in the front trunk bulkhead, so it shouldn't be too big of a deal The more I think about it, I'm pretty sure its just the location, being much higher than the fuel lines thats causing this. I'm pretty sure I have it mounted in the same place as the stock FI pump though? They were mounted above the passenger suspension console, below the battery correct? There was a bracket with two bolt holes there, so thats where I guessed the original was installed.

george, when you say"just below the battery" do you mean in the engine compartment? relocation time if that's the case. try to keep it as close to or below the level of the tank outlet tube.

sorry i missed your phone call. free admission to the museums in tacoma last night. the wife and i went out to beat the heat and take advantage of some free ac. pm sent.

k

Another thing you need to be aware of is "duty cycle". Things with copper windings (motors, solenoids, etc) lose power as they get hot. That's why they rate motors and solenoids for amount of "duty cycle" (or use) because the force/torque output drops the more the device is used. If you run a motor intermittently, you select a smaller motor. If you run a motor constanty, then you select a bigger motor and plan on the output torque to drop as it gets hot.

So yeah, if the pump is high and trying to drag gas uphill, it has to work harder and will heat up which causes the pump output to drop.

Hey Kevin,
No worries, hope you enjoyed your night out! I wish we had more museums around here! I always try to get my fix when I go to NE cities, they always have cool stuff.

Yes, its in the engine bay. I'll take a picture of the bracket I'm talking about tonight hopefully. It just looked like an obvious place for a fuel pump, but after finding a picture of a factory pump, I guess I see where its supposed to go. The factory pump was right above the passenger heater tube hole, correct? This is approximately where the pump was when I got the car, but it didn't seem like a great location to me so I moved it I think I'll go for the front mounted location, though I've never had problems with vapor lock yet. Thanks!

heres a picture of my setup. that blue hose runs all the way to the rear firewall. no ss lines. i have never had a fueling problem. and have many many miles of blazing heat on this set up. psi set to 2.0 at the TEE right before it enters the carbs.

Any pump run dry will run hot because they're cooled by the gas going through them, and if you keep running it hot it will fail. If you have another pump you can switch in try it, and definitely get it closer to the source so it's a pusher, but I suspect you still have a problem somewhere in the supply side. I remember someone telling about kinking a hose where he couldn't see it every time he put the fuel tank back in, for example. Something to check.