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Hi all. I had to put a pressure regulator inline at the front of my carb. I have it dialed all the way up (5.5 psi), however the carb still runs out of fuel when I go uphill or faster than about thirty mph or so. New fuel filters, hose and pump. Everything I've read on this site indicates 4 psi should be sufficient. Any ideas? Thanks,

Scott

You've already got marginally more psi at the outlet side of the pump than you should have - borderline enough to overwhelm the needle and seat. Your problem lies elsewhere.

The factory mechanical pump at 3-4 psi should supply enough fuel to go as fast as the car can go and sustain that speed. Pinched line? Undersized line? Failing rubber pump inlet hose? Floating crap in the tank that blocks in suction line? What's the float level setting?

I guess you have an electric pump and that's why you needed a pressure regulator? Why an electric pump? And how is it installed? But chances are your problem is related to one of the above.

Which regulator? I have a brand new fuel pump with all new lines, filter, carb, redone manifolds, etc. I was using a spectre one i believe, or maybe it was mr gasket. Anyway, i have a gauge on the carb side of the regulator, and it'd always be at zero no matter what i set the regulator at! Took it off, and stock pump is almost always at about 4. I was running out of gas the same way. I don't think there was enough pressure for the regulator to work properly.

You mentioned a new fuel filter. Was it new modern or old ceramic or just cleaned. I went thru that exact scenario with a ceramic filter. You could blow air thru it, gas would flow at idle and slow speed fine but get going and not enough gas would flow so it would "run out of gas". As O_D mentioned, the fuel flex hose is also notorious. Went thru that as well on another car. Looks fine on the outside but the inner lining dries out and cracks. Suction pulls a flap out into the stream and strangles the flow. Also check the tank gas cap vent and make sure there is one and it is open.

I've replaced the electric bellows type that was on her with a rotary style pump. It was already set up for an electric, the mechanical pump having been bypassed some time ago. The fuel filter is a modern inline type that I just replaced last week. Fuel tank has been purged and sealed and all of the lines have been replaced (modern fuel line that ethanol won't eat up, not flex line). I'm going to pull the top off of the carb and re-check my float level. It's acting like it isn't getting enough fuel, however I can't run the pump without the regulator, it puts too much in and floods the carb. I'm figuring that someone that owned my car before me replaced the stock mechanical pump with the electric because they couldn't find a rebuild for it. I would be worried about a rebuild kit that didn't have gaskets and bellows that would get chewed up by the ethanol in new gas. I've already replaced the bellows type electric twice, and done two rebuilds as well. I didn't know about the ethanol issues at the time.

With all that replaced, does sound as if the carb is a likely place to start.

If that checks out, specs on the 52 & 53 mechanical pump capacity are 1 pint in 45 seconds @ 4 to 5 psi, 1 1/2 pts on the 54s. No RPM mentioned those years but 500 RPM on the 55s so probably at idle speed. If the electric pump can't do considerably more than that just turning it on, then something is sure clogged so at least a place to start looking.

Ethanol-compatible parts for the mechanical fuel pumps have never been a supply issue, they were readily available even before the gasoline hit the market. There is however a problem if you were to buy NOS kits as they are not compatible and would fail quickly.

You say no flex-line; you must have one somewhere where the hardline fixed tothe frame makes the connection to the engine.

At least in my experience, electric pumps used for anything other than priming after long storage are more trouble than any mechanical pump ever was. But check the flow rate! If it's OK then I agree the problem is probably in the carburetor.

CHECK THE REGULATOR! Like i said, i used 2 of them and both of them worked intermitently out of the box. I don't trust low pressure regulators now, especially the one that has a dial in .5 increments. Add a gauge after it or hillbilly test drive quickly with a gas line to the carb and some kind of gravity feed setup. My regulator was the problem all along, i chased it for 3-4 days.

Court, I'm going to give my regulator a check and see if its doing what it is SUPPOSED be doing. If it isn't, I suppose I'm going to have to go with something else. I may just go ahead and rebuild the mechanical pump, as long as I can find a rebuild kit that isn't old stock off-the-dusty-shelf. I just want my baby to run dependably!

The kits from then and now are made from good fresh and modern material and many members here have used them. I have not heard any negative reports on their kits or rebuild services.http://www.maritimedragracing.com/antique_auto_parts_cellar.htm

Posters on another site mentioned they had problems adjusting regulators without having a continuous fuel flow for the duration of the adjustment. Didn't say which regulator or exactly what they were working on other than car had a carburetor and one regulator had two ports. That guy said he used the extra port for the gauge. Any chance that flow could be needed to adjust the regulator you have or the other brand with bad reviews?