Greetings All,

Mine is a 65 coupe with a 74, 350 cid engine. I'm currently running a Holly 650 carburetor, Holly mechanical fuel pump, MSD coil, Taylor 8mm spark plug wires, and the standard GM point ignition. The car had been developing symptoms of shutting down whenever I came to a stop. As a result, I kept the RPMs up with the throttle while slowing and in neutral. I suspected a worn ignition system and changed everything out to the above description. I also changed the fuel filter and installed a glass filter. After completing all the ignition upgrades, I attempted to drive the car. The engine starts up just fine but it quit 1 mile from my house. It acted like fuel starvation. I visually checked my fuel status and found the tank half full. I loosened the fuel cap and tried to run the engine but it ran for only a few seconds and only when I was "feathering" the throttle. After pulling the air cleaner and moving the throttle by hand, I observed accelerator pump fuel pumping fuel. After getting the car back home, I checked the fuel pump pressure and found it steady at 5psi. I believe the ignition system is good since everything is new and the air intake is good with no obstructions. All the fuel lines appear to be unobstructed. The only other problem must be in the fuel delivery.

Having explained all these details, could a new carburetor be in order here? Has anyone experienced similar problems? Any input would be greatly appreciated. Thanks guys.

Don

 

After it shuts down, how long does it take before it will fire up again. Even though you replaced the filter, there could be some dirt or rust particles already in the carb that are causing the problem.
Before you toss that carb, it couldn't hurt to take it apart and see if you have any contamination problems. This the non-stock inline filter I had on my smallblock 65 Coupe.

Mike T.

 

Thanks Mike, I'll check it out tonight.

 

You could also check the fuel lines. They have been known to get gooey inside from the new fuel. Or they're just old.
OR, you've got a punky ballast resistor. I had a 53 studebaker that would drive fine for awhile then quit. I'd go back out in an hour or so and it would fire and run fine again. A $2 ballast resistor fixed it. Dunno, just an idea

 

Years ago, my father had a similar problem. It ended up being a bad coil. Once the coil was replaced, the problem was solved. I don't know how you go about checking the coil, but I'm sure someone will chime in with an easy test procedure. Good luck, Roger.

 

I have a similar problem. Does the engine idle way down when sitting? Try this, pull the air cleaner off and see if your idle increases. Put your fingers over one or both bowl vent tubes. These are the 2 1/4" vert. tubes near the center of the carb. When you close off these tubes does the engine idle way down to a stall, it should. Does this feel like the problem with idle you're experiencing? Try spacing your air cleaner higher so the cover is spaced more above the vent tubes. I read that it needs about 3/4". Mine runs fine with the air filter off but will idle to a stall with the air filter on. I still don't know why it does this. I have spaced the air cleaner assembly 3/4" above the carb and still it will idle to a stall after a drive. Keep us posted.

 

I had a similar problem with my 70 Dart. Turned out to be a bad condenser.

 

Try pulling the needle valves off both the primaries and secondaries and blow them out. I have had similar issues that I was able to correct by cleaning these out. You will have to re-adjust your float bowl levels after doing this. All it takes is a miniscular particle to get caught in there and it can cause the car not to idle without giving it gas.

 

Typical Holley problem. Either raise the float level or add jet extenders to the primary side.

 

Dan Gurney once said: "Only change one thing at a time". I didn't follow that advice but did solve the mystery. My shutdown problem was a combination of a worn out Holly carburetor and possibly a clogged fuel filter. I know I did an overkill on this but changing out the carburetor was something I had wanted to do for a long time. I replaced the Holly with an Edelbrock Performer. This also called for a change in the fuel filter which appeared to be restricted anyway. I had previously done a pressure check of the fuel pump which indicated 8 psi. After removing the filter, I found it didn't flow the fuel as well as the new one which was clear plastic. I also did some research on fuel lines and learned how difficult replacing fuel lines in a C2 can be. To make certain mine were clear, I syphoned the fuel from the tank and pumped compressed air from the fuel pump intake line backwards into the tank. The airflow was fine and did not appear restricted. I knew I had good fuel lines, a good pump, a fresh filter, and a brand new carburetor. Electrically, everything had been changed out and was properly set. The car now runs beautifully, is responsive and most of all reliable. My goal for the future is to keep the fuel clean as well as the fuel lines. It does these cars no good to sit in a garage idle. I am now a believer they must be exercised and driven to keep them in shape.

Thanks to all who offered advice. Much appreciated.
Don