66 Mustang running rough .. any ideas?

Hi guys. I've got a 66 mustang. 289, 600cfm Carter carb. The problem I'm having is that the car starts up ok and runs great for about 5 - 10 minutes.
After it warms up, it will still idle fine at a stop, but when you give it gas, it acts like it wants to die for a second until you get above and beyond that rpm range. This will get progressivly worse if you keep driving it to the point to where when you accelerate it dies.
If you let the car sit for an hour or two, it will start back up and drive fine again for 5 - 10 minutes and the process repeats.
I've got the points set properly, the timing is advanced by about 3 degrees, but the distributor WILL NOT move to let me adjust it back. I'm not super mechanically inclined, but I can replace basic parts and try a few things if someone has some ideas. Trying to avoid having to take it to a shop as most of the mechanics seem to be interested in only working on new cars they can plug a computer into. :(
Thanks in advance!
-Wes
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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
--
ThunderSnake #9 Warn once, shoot twice

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

strange things. Have you checked for manifold leaks with propane or carb cleaner ?
Bill
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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?
--
R. J. Talley
Teacher/James Madison Fellow
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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
On Sat, 25 Oct 2003 13:36:39 -0600, Wes Fisher wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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.)
--
Every day is a good day- it's just that some are better than others.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
still the carburetor acc. pump john

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.