![]() I have one of those for lack of a better term "vibrating pumps" sitting around and maybe when they stop the plunger retracts allowing fuel flow? On using the electric fuel pump as a "primer." Once the electric pump is shut off wouldn't it become a restriction to fuel passing through it? And likewise, on the front end, wouldn't the mechanical pump become a restriction unless the car was cranking (which we are trying to prevent) during the priming process? If neither is occurring then great, but could someone explain how? I've only opened an electric pump once (a Conelec) and the vanes would seem to inhibit fuel passing if it wasn't turning. I wonder if that isn't a contributor to the gas evaporating. On older car most people just let it vent to the atmosphere. On most early 70's and up cars there is closed (charcoal canister) system that it connects to. One thing I did notice is that the bowl vent is rather large. BTW, the engine is a 350 Chevy and the Edelbrock a 1406. Yet splash a little gas in the carb, turn it over and generally it will start right up. And as with his situation cranking endlessly doesn't seem to fill the bowl. Even a few days and the bowl is empty on my Edelbrock carb. I realize an inline electric priming pump will cure the symptoms, but I'd like to know why. At most, if a car Sat for a month, I'd have crank for a few seconds to get some in the bowl, but that's it. I've run Edelbrock carbs on a cars in the past and never had this issue. I've run mostly Holley carbs on everything I've owned from muscle cars to old relics to EFI reversion.never had this issue. I've got old Fords with Strombergs, wcfb, and even a Holley. Why won't the fuel pump fill the bowl within a few seconds? Even sitting for weeks.īut assume it's all evaporating within a couple of days. I agree that the fuel is evaporating, however, none of my other carbureted cars have this issue. However this is the only car I've got with this issue. Turning the engine off when "hot", just after normal use, speeds the evaporation.I agree. You can hear it change tone when the carb bowl is full.then turn it off and let the Stock pump take over when the engine starts I've done this on ALL my carbureted cars, and it's CURED the problem completely. I've put a toggle switch under the dash, and use it to prime the carburetor before starting. The best way to remedy this is to properly install a low (3-4lb) pressure pump as close to the tank as possible. ![]() The vapor pressure of modern fuel is such that it evaporates out of the fuel bowl of the carburetor. Think about it.HOW is the fuel going to get past the needle and seat in the carburetor and siphon back down to the pump. ![]() Rusted lines, cracked lines, plugged lines, bad flares, kinked lines, crushed lines, but never pin holes that didn't obviously leak or smell.I have neither.but they could still be there I suppose. I've been working on old cars for thirty or forty years and have never run across pin holes in fuel lines. Even if there were pin holes, the line between the pump and carb should remain full of fuel.Īll that said, pin holes would definitely explain my symptoms. What is confusing is the carb itself going dry. While trouble shooting last month, I blew into the line at the pump back toward the tank to ensure there was no blockage our leaks.and I recognize that the type of leaks you're talking about may not be obvious. About half the time was in New Mexico, so a very dry climate. The lines were all new and the car was stored inside for all but a couple months. A new fuel line and problem solved.While I won't rule that out, it's low on my list right now. Even then the engine still ran but I had to prime it every time I started it. I had the exact condition, after two fuel pumps and two carburetors, I finally determined the fuel line was leaking, and it was. blow on a rubber hose and spray the fuel line and clasps with soapy water and you will probably see bubbles. ![]() Pressurize the fuel delivery line with just ounces eg. When it sits the air will displace the fuel and you will have problems starting. If the hole(s) is/are small enough the pump will overcome and the engine will run just fine. Your problem is most likely a pin hole in the fuel delivery line and the fuel is leaking out and the pump is sucking air. I don't think the fuel will bleed back in to the tank, if you disconnect the inlet fuel line at the pump gravity will deliver fuel to that point. ![]()
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