Fuel Line size

[zak]

Some of you may remember that I won a m342a2 in a auction recently. It was missing the starter, exhaust system and the radiator. Well I got the exhaust back on and found a starter that I had to rebuild. As I was installing the starter I discovered that the fuel line from the primary filter was bent and crimped and the flex hose was missing to the injector pump. My fuel line is 1/2 inch copper from the filter but the fitting on the pump is for a 3/8's flared. The TM 9-2320-361-20p is of no help on sizes. It shows in fig #25 that the fuel line #21 is "make from tube" and the flex hose #20 is just "hose assembly". Not to B**tch but all my m37 manuels tell sizes, have good pictures and drawings. Be that as it may, I went to the local auto part store and got 3/8's steel brake line and had them make a flex hose to connect my new smaller line and the pump fitting. After hooking every up and spending about a hour trying to get the in tank pump to work(bad ground), I let the tank pump run until I could hear fuel running back inthe tank. Ater a few engine turns with the fuel shut off on I tried it to start it. I WAS AMAZED that it started after no more that one or two seconds. The oil pressure came right up and I could hear the whisle. It was almost as good as s**. I only let it run less than a minute(no radiator yet)
Now my questions are:
I allways was taught that copper was a no-no in any auto/truck application and
is my 3/8 line to small for the fuel supply?

 

[cranetruck]

Most of the fuel lines are copper on the deuce (and other MV's as well). The feed is 1/2 inch until you get to the ca 1 ft link you replaced, it is 3/8 inch. What you ended up with is standard for size.
The return lines are 3/8 inch copper.