Hi all,
Having a slight problem with the fuel automatic on our Stanley, we set the pressure at 120PSI and then when we start driving, the pressure constantly changes, sometimes going up to 180PSI. Does anyone know why this is and is there a cure? Thanks. George.

When replumbing my car, I managed to get the fuel automatic connected incorrectly, which caused it to exhibit some very puzzling behavior. It seems so simple, but is not idiot-proof if you can find a big enough idiot. However, if you haven't done significant disassembly and repiping, it doesn't seem like this would be your issue.

Perhaps intermittent sticking of the needle valve in the seat? Does pressure ever move from 180 to 140, and if so, does it happen in one quick rush?

At least the diagnosis of this problem could be more convenient than some, as the fuel pressurizing system can be exercised without running the car.

Kelly

With the proper air level placed in the fuel pressure tanks when first pumping up your fuel pressure, the fuel pressure gauge should not waver any more than about 10 pounds above the set fuel by-pass pressure of the fuel automatic. If when traveling, the fuel pressure gauge needle starts to bounce excessively, then more air volume is requred in the fuel pressure tanks.

The fuel automatic bypasses excessive fuel and pressure back to the fuel tank. The ports in the valve are small and can become plugged with crud; pressure will rise or bypass intermittent depending on the obstruction. I would clean this valve first. If the fuel line back to the tank becomes plugged at the tank the same thing will happen. I had a fuel tank on my 1920 that was very rusted. I had to make fittings to go high above the bottom of the tank. Eventually I had to clean and treat the tank.