Fuel System: Fuel pump won't deliver, unless...

[Steve Winzar]

Hi all- There is a thread running currently regarding electric fuel pumps and I am interested in the comments some of us have made regarding priming. I did not wish to hijack the thread so I will bring my problem up here instead. I have found that my recently acquired 1962 Hawk will start fairly readily when It is parked nose pointing downhill, but if I park uphill or on ramps (with the front of the car up) it won't start. Investigating this, I found the Carter fuel pump not delivering fuel to the carb and appeared dead dry. No amount of cranking resulted in fuel coming up from the tank. I replaced the pump with a rebuilt one (even though both worked fine under a manual test I performed off the car) but identical problem exists. It seems the pump does not want to suck fuel up the line against gravity and the internal valves don't seal well enough whilst the try to pump air alone. It will only work if I manually prime the whole system first. The whole idea of an auxilliary pump is interesting me now, but I really would like to know why the conventional arrangement won't work. BTW I have no filters at all and I've also undone the fuel cap during tests. I can easily suck fuel up from the tank through a tube so I know it isn't restricted.
What's the problem?
Steve

[bezhawk]

Where is your electric pump mounted? Most electric pumps do not self prime well, therefore it is usually the practice to mount them as close to the fuel tank as possible.
They push fuel much better than sucking it.

[Steve Winzar]

Hi Brad- I don't have an electric pump installed yet (I have one in spares I can install if I wish), just the standard Carter up front for now, but getting it to work uphill once left for a few days is the problem.

[studegary]

It sounds like you may have a small air leak in a line (hard or soft line). Sometimes these are hard to locate - may be under a clamp on a hard line or a flexible line with a crack that doesn't always show).

[TWChamp]

I was just going to post the same thing Gary did. I'd check the flex hose for a tiny air leak.

[T.J lavallee]

Modern gas evaporates quickly leaving your float bowl dry if you park your car for a week no matter if it's parked on a hill facing uphill or down or on level ground. An electric pump will replenish the bowl with fuel enabling easier starts. Install a switch to shut the electric pump off once the engine fires. Your problem may be debris in your original pump (You say you have no filters) and or the diaphragm. There's no telling if the rebuilt pump was rebuilt correctly. Everything has to be replaced exactly as it was before it is disassembled. You have to mark eveything's position. A weak diaphragm will allow fuel to be pumped when the vehicle is facing downhill but not uphill where there is more pull required. A pinhole in a fuel supply line could also cause this type of problem.

[kxet]

Mine had pinhole leak in flex hose feeding fuel pump,never appeared wet.