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Return fuel line installed

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  • #16
    Presuming you’ve not yet replaced your core plugs, you dig & flush all the muck out through those openings. For me a coat hanger & a hose and/or power washer are the tools of choice. It’s a nasty dirty job but you’ll only have to do it once.
    ...and yes, the muck will be worse toward the (lower) rear of the block.
    Oops, Felix beat me to it!


    • #17
      P.S. I also run a return line. The setup has a 100 micron filter between the tank and electric pump, a regulator with return line, a 10 micron filter before the carb. The return line dumps into the tank on the opposite side, where the station wagon filler would be fitted. The regulator may not have been necessary, as the pump puts out 7psi max, but with the return line it made the job easier and with the constant flow I have cooler fuel.


      • #18
        I am not opposed to a fuel return line, but I nave difficulty understanding the merit in the assembly. I assume it is something to do with the fuel boiling in the fuel line/pump etc. What ever is on one side of the diaphragm in the pump will be delivered to the other side be it air/vapor or liquid. I performed an experiment with a fuel pump by placing an attached 10 foot length of hose into a container of a hydrocarbon/solvent and stood on a 10 foot ladder and actuated the lever and 5-6 strokes there was fuel delivered to the out let with a 6 foot stream. My point is the fuel pump will move vapor as well as liquid. If for some reason the fuel was to boil in the pump it would not take any more than a few strokes to clear said vapor and replace it with liquid fuel from the tank.

        After extensive discussions with a journeyman carburetor service person we concluded that the engine failure was caused from over fueling ie fuel boiling in the carburetor bowel and overflowing down the throat and over fueling the engine. Continuing to actuate the starter only worsens the condition as more fuel is delivered to an already over fueled engine. The usual procedure for this "condition" is to wait for the high temperature to reduce somewhat, but what is really happening is the excess fuel is evaporating to a point where it will restart. These engine failure conditions are frequently referred to as "vapor lock". To date I have not had it explained to me what a "vapor lock" is and what really causes it. From my understandings, the conditions of fuel boiling is in the carburetor, and not in the fuel pump. The most common factors that cause boiling fuel is elevated temperatures. Engine cooling systems are a fixed operation, eg fans, radiators circulation water pumps and a quantity of liquid to transfer the generated heat to the radiator where it is air cooled.
        Engine operating temperatures can be controlled by variable temperature thermostats. Too high of a thermostat can be detrimental in warmer air temperatures. In sufficient liquid coolant in the block can also cause increased engine temperatures, this can be as a result of debris in the block or poor maintenance and low level of liquid. Slightly retarded timing can also contribute to higher temperatures. If you bring all of these issues together at the same time, low coolant, high thermostat, slightly retarded timing , 100* air temperatures, restricted radiator and low speeds you will most likely become a victim of "vapor lock", perhaps a return fuel line will fix it.


        • #19
          Originally posted by mw2013 View Post

          how do you assure water jacket in engine is clear? flush?, if not what happens? hot spots? is this a Studebaker only issue?
          From what I could see of yours, through the freeze plug hole pic you posted, it appears yours haven cleaned, and cleaned well. JMHO