Every vehicle I've seen from the 50s through the early 80s with a mechanical pump has a pickup tube in the top of the tank that is usually connected to the fuel level sending unit and they have a sock type filter attached to prevent debris in the tank from being sucked into the tube. They don't pull the fuel out of the lowest part of the tank because the dirt settles in the bottom. Heavy trucks have a tube that is independent of the sending unit. At work, we had a Mack truck that wold occasionally die on the road. When the fuel filters were removed they would be empty and if it was in a quiet area a sucking sound could be heard. After sucking the fuel out of the tank I found the plastic cap from a bottle of fuel conditioner. It would sometimes get sucked up and block the pickup tube. The suction would hold it there until the filter was removed breaking the vacuum. A true fuel cell is designed with a large removable cover on top so a bladder can be installed and removed. They usually incorporate a screen so the foam doesn't get into the pickup tube. If there isn't a removable cover, it isn't a fuel cell. It's just a fuel tank. The random occurance makes me suspect something in the tank is blocking the pickup tube.
Ok guys I discovered I have a newer style fuel pump with the return blocked off and here are the specs. Fuel Type(s): Gas GPH (Free Flow) Rating: 40 gph Inlet Size(s): 3/8 TUBE in Outlet Size(s): 5/8 -18 UNF-2B I.F. in Pressure Rating: 7.5 - 9 PSI U.S.C.G. Approved: No My buddy thinks I need the older style without the return line, and it has these specs. Fuel Type(s): Gas GPH (Free Flow) Rating: 40 gph Inlet Size(s): 3/8 TUBE in Outlet Size(s): 5/8 -18 UNF-2B I.F. in Pressure Rating: 5.25 - 6.5 PSI U.S.C.G. Approved: No So now my question is would the higher pressure create the issue I'm having?
Blocking the return would probably create more trouble than the higher pressure. The pump with the return is supposed to have a constant flow of fuel thru it. I However that should produce a more consistent fuck up than a once in a couple weeks
If its sucking air which is possible you should see air bubbles in the glass filter. Had this happened to me on a Holley mech. pump once. The adjustable one with the rubber gasket around the perimeter. It can suck air from any number of locations in the system and not leak a lot of fuel. Rare but possible.
I have an Edelbrock on my daily 72 international pickup. Had intermittent problems like yours. After having the carb professionally rebuilt twice, I finally added a regulator and everything was fine. They don't like pressure over 5 lbs( I run at 4). I think the stock mech fuel pump action surges a little. This causes the float to flutter. I have since installed 4 more regulators on friends rides and cleared up their issues as well. It's now item one on all edelbrock installs. Posted using the Full Custom H.A.M.B. App!
ok I'll get the right pump on there with no return and if that doesn't fix, I'll add a regulator. I dont think I've seen many pics of roadsters with regulators on them. I guess its mounted on the firewall near the carb?
One of my friends has a street rodded 32. He ran a line out of his mech pump to the frame rail, mounted the reg there, followed the same routing back to the pump and up to the carb. You have to look really hard to see it. Another friend mounted his on the manifold at the carb, but it's hidden quite a bit by his air cleaner in his 55 Posted using the Full Custom H.A.M.B. App!
You really should measure your fuel pressure. Do you have a regulator now ? Because the info you posted says you have 7.5 -9 which is 2x what your eddy carb wants to see. But since the return line is blocked there's no telling what it is really. If you drop to a 5.25 - 6.5 pump you'll be just over the eddy requirement. Not sure how an over pressure situation causes a random loss of pressure. I'm sure there are puzzle pieces not mentioned.
I'm not sure as to why it happened, but on my friends 55, his acted exactly as described, seeming to create an air lock or something in the line. He would be fine, and suddenly stall on the highway, no fuel in the bowl. He went to electric, changed that twice, changed fuel tank and line, added a return line,and was wanting to sell the car out of frustration. Finally added the regulator and it fixed it. Like I said, that is now the first thing I do with any Edelbrock problem. Posted using the Full Custom H.A.M.B. App!
My car did the same thing, it was the rubber hose, it separated inside and was collapsing. The outside of the hose looked good.
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