My 77 F-150 with 460 has been hard starting when cold lately. I've think I have found the culprit. When I vacuum tested the Vacuum Advance diaphragm it held vacuum but the advance lever failed to move.
Is there a way to free it up without breaking anything?

 

That shouldn't effect starting at all just open throttle driving. Couple months ago I tried to get mine free because truck would knock bad going up hills on the highway. Couldn't get the vac advance free and couldn't get apart it was so rusted so got a reman dizzy from napa and 3 miles after installing the counter weights blew apart and sheared the shaft. Got another only this time new and so far so good. Got a Davis Unified on order just in case though.

 

Hmm, I thought it retarded the timing when starting for an easier start; maybe I'm wrong.

 

No just base timing controls starting. Vacuum advance advances the timing while you're at part throttle for gas mileage/driveability.

 

Do you have points or elec ignition? Also, check the cap contacts. I found that the aluminum ones don't hold up as well as the brass ones and cold wet weather seems to aggravate it more.

 

Lots of things it could be. the choke would be the place to start. if pumping the gas makes it start better your choke is too lean.

 

It has Duraspark2 with a manual choke on an Edelbrock 1406.
Good spark, voltage and new ICM.
It starts great after a warm up.

 

Check and see if your choke is closing properly. cables get out of whack too.

horribly low compression can cause poor starting.

If you have good spark then fuel is about the only other place to look.

 

I got the vacuum advance to free up with penetrating oil and tapping it gently.
You were right Butcher, it did not effect the cold starting.
I checked the carb and the two squirter nozzles were just dribbling fuel (not squirting).
I cleaned them and had to order new non-stick gaskets. Somehow the one I had stuck.
Anyway, waiting on them and a new steel accelerator pump. I'm pretty confident that was the hard start issue.
Thanks to all of you for your advice.

 

If you lose these guys I got ya covered. Never ever work on your distributor in your milling machine vise unless you clean up the scrap chips FIRST.