66 Mustang running rough .. any ideas?

"Wes Fisher" wrote in news: snipped-for-privacy@comcast.com:

Some of the older fords had a plastic filter on the end of the fuel tank pickup. They were known for pluging after a while. gasahol agaravated this problem. Try removing the gas cap, then the inlet hose at the fuel pump, then use a air pressure hose and blow back through the tank. If your lucky it will blow the filter off the pickup. other wise you will have to drive it untill it is acting up severly and pull the top of the carb and check the fuel level. If it is a fuel pump or supply problem it will be low. (or just check the fuel pressure as you are driveing.) KB

I'd do a cold and hot fuel pressure check, mechanical pumps used to do strange things. Have you checked for manifold leaks with propane or carb cleaner ?

Bill

Another less likely possibility: pinhole in the fuel line between the tank and the pump. I've seen this before; at idle fuel delivery was adequate, but at increasing throttle, the pinhole starts to feed air into the line, decreasing fuel volume and rendering the pump unable to pump. This didn't cause an off idle stumble in my case, just fuel starvation after opening the throttle. The off idle stumble sounds like dirty air or fuel filters, too lean of an idle set, or a fault in the accelerator pump. The idle mix and accel pump shouldn't cause stalling after established part throttle operation, though. How's the float level? Vacuum leaks? Also, I would guess that 3~ is too little initial spark lead, but I'm hard pressed to believe that alone would cause these troubles. Sometimes distributors get pretty gunked up and stuck; I've had to use PBlaster or kerosene to get them loose before.

Mark

the carburetor has an accelerater pump on the front. when you call for quick power by depressing the gas pedal, it squirts an extra shot of gas into the carburetor to stop hesitation. it is replacable from the outside front of the card. john

The 66 289 Fords used a combination vacuum and centrifugal advance for the timing. First take a good look at the diaphragm in the vacuum advance. It may be leaking causing the timing to be off. Cold engines cannot handle the advance that warm engines can. Second, use a good timing light and establish that the timing is changing as the engine warms up. The inability of the distributor to rotate is cause for concern. Have you tried pulling it yet?

First off you need to set the timing. Then check the dwell. Points can appear to be gapped right but the dwell can be way off. Increasing point gap decreases dwell and vice versa. Dwell meters are inexpensive. Also check the timing advance. Once you have the ignition operating properly, start looking at the fuel system. I'm not that familiar with Carter carbs, but they must have a website. If it's anything like Holley's website it will have lots of info on your carb. Be sure your choke isn't sticking. Running fine when cold but not when warm is a symptom of a choke not opening fully. And if the car was running fine until you changed something, whatever you changed is probably the problem. (or something you moved/removed during a repair didn't get back just right.)

still the carburetor acc. pump john

"johnny" wrote in news:0FXmb.37215$Tr4.72347@attbi_s03:

Why does the pump work fine when the engine is cold and not when it's warm? I don't see that as the problem.

I am not sure unless the auto choke supplies enough when cold. Anyway the acc. pump used to be included in a carb. rebuild kit for $20. ma be a cheap fix. john