This 1974 GMC 3/4 4X4 was dads until he died and has developed an issue. It's run fine for the past 40 years and just recently started running out of fuel after 20 minutes of driving.....while both tanks are full (I installed a glass filter by the carb). I changed both sending units, 3 mechanical pumps, one electric, eliminated the the tank selector switch still running out of fuel after it gets hot. Back to mechanical A/C Delco original same problem. Replaced all rubber fuel lines and still running out of fuel.
I couldn't run it for long before it runs out of fuel.
Until...... I bypassed the factory fuel lines that run inside the frame rail by the 40 year old headers with strategically run rubber fuel line. Problem solved!!!!!
Why are the fuel lines suddenly getting so hot the fuel boils on it's way by after all these years?
Side note..... just finished rebuilding the motor on the Hickey Sidewinder winch. Wiring is proving difficult.