'68 Barracuda Notch

rymanrph said
When I swapped the engine over from the red car, it got a new electronic distributor, cap and rotor and I upgraded to Trailbeast's HEI system. I put in new plugs and wires as well. The timing is set to 13° of initial timing currently with my idle rpm just over 900. I did try to adjust the idle mixture screws as well; I don't remember what they are set at though, but it didn't improve anything when I adjusted them. I haven't adjusted the floats.

When the car first starts, unless you give it some gas, it just wants to die. After a little bit of time it will just barely idle without shutting off. Putting it in gear and giving it any kind of gas just makes it want to die. I have to get the car rolling at idle before any significant amount of throttle. Once the car has warmed up a bit, it doesn't want to die from a stand still, but there is a lag between pushing the pedal and getting anything to happen. When it does finally move, it feels almost like a surge. I'll chirp the tires backing out of the driveway.

The car runs hot at about 2/3 up the gauge while moving and if I slow down or stop, it starts to creep up from there. I've read that bad tuning could cause this. I have a 26" radiator with a shroud. It seems to provide good airflow. I have an external transmission cooler in front of the radiator, but I can't imagine it blocks enough airflow to cause that much of a problem. The fan clutch seems to be working. I don't know the condition of the thermostat or water pump.

And on top of everything, while I was out driving it tonight, the headlight switch (I think) finally gave up the ghost and I lost parking lights and tail lights. The fuse seemed good and I know it could be something else, but the dimmer function has been real spotty recently, so I'm placing my bets on the switch.

I made a quick drawing with a few features pointed out in case you are not familiar.

1) Check the float level. That affects every circuit in the carb. On each end of your carb you have a float bowl. On the top is the adjuster nut for the needle / seat height. On the passenger side of the carb are two sight glasses or removable brass plugs. If you have the plugs, you put some rags below them and remove them. If you have an electric pump it is easier because the engine does not need to be running. With the pump running, or engine if the car only has the cam driven pump, you put a box end wrench over the adjuster nut and slightly loosen the lock screw with a flat blade screwdriver. If the fuel is running out of the sight hole, turn the nut until it just barely stops. If you have the sight glass style you want the fuel to just barely be visible at the bottom. Once you have the height adjusted you tighten the locking screw. Do this for the front and rear float bowls. Put the sight plugs back in when you are done. Be careful that you do not get too much fuel collecting in the rags or on the manifold, it is easy to start a fire if you are not careful. The sight glass style may take longer to adjust, you just have to be more patient. If the level is too high you have to wait for the car to use the fuel after each adjustment as you are lowering the level. With the sight plug style it is easier, it just drains out the side if it is too high.

2) Once the floats are set, then adjust the idle mixture. With the car off, gently turn the idle mixture screw clockwise until you feel it seat. Gentle... do not run it down tight. Count the number of full turns it takes to get there. My normal starting point is 2-1/2 full turns out on each side. Once it is seated, turn it out 2-1/2 turns on each side. Start the car. I get a tach feed so I can watch the rpm to do the next part. You can also get a helper to watch or, just listen to the engine. Turn the idle mixture screws slowly in / out on each side until you get the highest idle speed. Check each side independently. Turn the idle speed screw in out to drop or raise the idle occasionally as you go to maintain your target idle speed.

3) Check the accelerator pump. You can push the lever with your finger or blip the throttle. When you do so fuel should come out of the squirter. Your symptoms sound like an accelerator pump issue, but they could just as easily be caused by low float level.

Checking power valve and a few other things require taking the carb apart, you should have gaskets and maybe a manual or some other reference before you tackle something like that. Checking the floats, adjusting the idle speed, and adjusting the idle mixture take care of most issues. If you adjust the float level, go back and make sure the timing is good. Every other adjustment seems to affect timing.

Good luck.