I'm at a bit of a loss and need some advice, I have a 216 in-line six in my '50 Chevy. It runs beautifully at lower speeds around town, but when I get it going on the highway, really give it gas, after about a mile down the road, it starts to stumble and then dies. It sounds almost like a small plane coming in for a landing. The fuel pump has been replaced, the carburetor has been rebuilt, the coil has been replaced, Spark plugs are new, distributor looks like it's in good shape, does anyone have advice that may help narrow the problem down? Or point me to a thread that might help me out?
Definitely seems to be running out of gas. Seems to be getting enough for easing around but not enough for full throttle consumption. Do you have a stopped up filter, pinched line, low float level?
So far, we've installed an in-line fuel filter, and cleaned out the carb. None of the lines appear pinched, and the float I believe is at the correct level.
It is probably either fuel or spark. Try running the engine up to redline in first gear. If the engine will pull under load to redline in first without sputtering, then the spark is probably OK and you have a fuel delivery system problem. If the engine sputters before redline in first, it is probably spark. Jon
Partialy clogged pickup sock (screen) in the tank. Try blowing some compressed air (not high pressure) back through the fuel line towards the tank. KK
New gas cap that you put on recently? Loosen the cap a bit and see if it acts up. The other thing is trash in the gas tank as Kool_Kat57 suggested. When these trucks sit for a while the gas caps seem to come up missing all too often or small kids think they are a great place to stuff things in. Some models also had/have a shut off valve under the floorboard to shut the gas off if you have to take a line loose and that valve may be partially closed and not letting fuel through. If those things aren't the case start looking for a brass fitting that has been changed as I had a problem on the 57 Panel that I had were someone had put a natural gas fitting in the fuel line with a very small orifice in it that let the truck idle but caused it to run out of gas until you let up on the gas for a few seconds and hit it again. Twisted fuel lines at the tank, pump or carb can cause the same problem.
another thing to check is your heat riser valve http://chevy.oldcarmanualproject.com/shop/1948_51truck/51ctsm0605.htm Fig 4 make sure the counterwieght is not stuck.
Thanks everyone for the ideas, Found out there was a fuel filter at the base of the gas tank on the under side of the body. I pulled it off and replaced it and now the truck runs great.
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