blue69

Carb heat sheilds are in place, Stock location of lines and exhaust. I added the electric pump trying to improve the problem. Neither pump seems to make much difference. Replaced fuel line to eliminate potential problem. Several have suggested crap in the fuel tank but Ive got two, both clean, and both result in the same problem. Seems worse going up hill. Is there some inherent tank problem with dip tube,rtc that shows up in these cars? I am running a B-cam with SU's. Ive tested both pumps for flow and pressure and both seem correct. Reset float levels which appear correct. Unless these carbs just cant deliver enough gas When testing the fuel line with my vacuum gun, it seems like there is back siphon pressure as the line will completely suck the reservoir on my vacuum pump dry when you release the vacuum, Maybe normal but seems odd to me, Ive tried it with no fuel cap, with recirc line attached, detached, etc. Nothing seems to make a difference, Ive questioned if the feed and return were reversed, The larger line matches up with the return, which seems somewhat backwards nut based on the original fittings seems to be the only way it can be connected. Any suggestions would be appreciated!

Anyone had problems with fuel delivery on a U20 roadster? Using Nissan electric pump at rear and stock mechanical pump to SU's, Car runs good up to 60/70 mph then stumbles or struggles to get past after a few minutes. We switch tanks, lines, etc and still happens. Ran the car out of gas at Road Atlanta and stalled it coming off the track and climbing the hill. When this happens, you can typically see a very low fuel level in the filter when you stop. Tried everything but cant seem to find this one. Wonder if this could somehow be vapor lock or fuel boiling in bowls?