Fuel pressure on '67 L71?

[Norris W.]

So I've got a friend that just purchased a '67 L71 Roadster long distance. I kinda' helped him through the process to the extent that it's possible without a face to face and as near as we can tell he bought a good car. He's having some hot start issues and has noticed that the front and rear carbs appear to have some internal fuel leakage after it's shut off, and possibly even when idling. After the purchase the car had an external fuel pump leak and he bought a supposedly correct NEW Delco Replacement from David Crane. The local shop (who's not Corvette friendly in my opinion) has him worrying about fuel pressure. We live about 5 hours apart, so not something I can help with. So 2 questions: Chances that a stock replacement Delco pump is overwhelming the needles? .......... AND........ since he's convinced my friend to let him test the pressure how much can the stock needles and seats hold assuming in good shape and what does a standard Delco mechanical pump usually put out? My recommendation is to just go through the carbs. Incidentally, at my suggestion he has just joined the NCRS within the last week, but hasn't registered on the forums here evidently.

[Danny P.]

Re: Fuel pressure on '67 L71?

Hi Norris, stock pump should have a least 5 to 7 PSI anymore like 9 would knock off the needle and seat to start try adjust the floats when running you also may have dirt in needle and seat .

[Norris W.]

Re: Fuel pressure on '67 L71?

Thanks Danny. When fooling with non original stuff with electric pumps I've always set the pressure at 6 max. Since we don't know the precise recent history it's also occurred to me that if somebody has had ethanol in it without changing the two rubber gas lines that he could be getting some rubber crumbs in the fuel system. That puts us back to going through the carbs which was my initial advice.

[Danny P.]

Re: Fuel pressure on '67 L71?

Thanks Danny. When fooling with non original stuff with electric pumps I've always set the pressure at 6 max. Since we don't know the precise recent history it's also occurred to me that if somebody has had ethanol in it without changing the two rubber gas lines that he could be getting some rubber crumbs in the fuel system. That puts us back to going through the carbs which was my initial advice.

Get rid of the rubber hose's and install proper steel tubing and blocks

[Norris W.]

Re: Fuel pressure on '67 L71?

By rubber hoses I meant the short hose from the tank sender to the steel line at the rear and from the steel line at the front to the inlet on the fuel pump. All of the fuel lines are correct.

[Danny P.]

Re: Fuel pressure on '67 L71?

Ok I understand you may want to go through your complete fuel system from cleaning the tank to the Carbs. and you may have to start to restore the carbs. at the same time .

[Norris W.]

Re: Fuel pressure on '67 L71?

Agree 100%

[Michael K.]

Re: Fuel pressure on '67 L71?

Thank you Norris Wallace for all your help... I am eternally grateful!!!

[Rich G.]

Re: Fuel pressure on '67 L71?

I have. 68 L71. Same set up. I’d start with checking float levels in the end carbs. Many people set them too high according to the guru who recently rebuilt mine for the same reason you describe. Also, they are simple and inexpensive to overhaul. Mine needed new needles and seats and gaskets. Cost $80 each here in high priced NY.

If they leak when the car is running it is very noticeable as it won’t idle and loads up below about 2000 rpm. My experience. YMMV.

Rich

[Michael K.]

Re: Fuel pressure on '67 L71?

thank you Rich