I am trying to tune the carb on my Ranchero and hope someone out there can help me. I have the Motorcraft 2150 2bbl on a 400 in a 1978 Ranchero GT.

The car is very hard to start. Once it does start I have to give it gas for about 5 minutes until it warms up. After that it runs fine. I have the idle set at 630RPM (the valve cover decal shows 600RPM /-75RPM). If I set the curb idle at 900RPM it runs much better at startup but idles too high once it warms up.

As near as I can tell all the vacuum lines are hooked up correctly. The car pulls 10in of manifold vacuum at idle. Does anyone have a good method of tuning a carb using normal tools (like a vacuum gauge and a tach)?

 

First and foremost: I think everyone will agree that most Fords are cold natured, therefore the choke must be set and work properly, you most likely have an electric choke on your 2100 Autolite carb, you should make sure that you have voltage to the choke, then check the operation of the choke linkage and lubricate as nessessary, then set choke to specs. also listed on your valve cover tag, this will also show the proper "choke idle" speed which is easily adjusted by a screw on the choke linkage that is faceing the firewall on the passingers side of the carb, this screw is a little hard to get to, then with all that done, and engine at operating temp, adjust the air/fuel mixture screws located in the front way at the bottom, to give the highest rpm, then lastly set the "curb idle" speed to specs, also be sure before you start all this to change your fuel filter, and if you really want to maximize your engines performance before you make all the carb adjustments fill up with premimum gasoline and advance your timing past factory specs just until the engine barely pings or barely does not ping on accelleration, Good Luck !!!

 

 

if your carb is only pulling 10 inches then you have a leak some where. have you checked your PVC valve lately?