The 1979 Ford F150 was equipped with either the Autolite 2150 two-barrel carburetor or with the Carter YFA one-barrel carburetor. Although both models are reliable, they do tend to fall out of adjustment over time. Working on either carburetor can be an intimidating task due to the number of components they feature. Some general familiarity with carburetors is helpful in adjusting either model, as a mistake could be significant enough to prevent the engine from starting until the mistake is remedied.
Adjust the float level by first removing the screws that secure the top of the carburetor to the body of the carburetor with a screwdriver, then lift the top off of the carburetor to access the metal float. Measure the distance between the top of the float and the carburetor's frame with a dial caliper. The distance must be 7/16 inches. Adjust the distance by depressing the tab on the back of the float. Lower the top of the carburetor onto the body and install the retaining screws.
Adjust the accelerating pump setting if necessary. The accelerating pump is concealed by a square metal cover at the front of the carburetor. A linkage extends from the pump to the driver's side of the carburetor where the linkage fits into one of four holes with a clip. The holes are numbered from 1 to 4, with 1 being the bottom hole and 4 being the top hole. The factory setting calls for the linkage to be fitted into hole number 2. The reaming holes are used for extreme atmospheric conditions. Press the clip toward the linkage while pressing the linkage away from the clip to disengage it. Insert the tip of the linkage into hole number 2 and press the clip into the linkage.
Return the automatic choke valve to its factory specification by first loosening the choke's cover, located on the passenger's side of the carburetor, with a screwdriver. Turn the choke cover to the "3 Rich" mark stamped into the cover.
Adjust the float level by first removing the screws that secure the top of the carburetor to the body of the carburetor with a screwdriver, then lift the top off of the carburetor to access the metal float. Turn the top of the carburetor upside down and hold it at eye level. Note that a metal pin is located directly below the float's arm. The arm should be resting on the pin. Bend the float arm until the arm touches the pin.
Adjust the dashpot if necessary. The dashpot is the disk-shaped component located underneath the choke housing. Note that one bolt enters the front of the dashpot and a plunger is located at the center of the back of the dashpot. Operate the engine until it reaches normal temperature, then press the plunger into the dashpot with a screwdriver. Measure the distance between the top of the plunger and the front of the throttle linkage. Turn the dashpot bolt with a wrench until this distance is between 3/32 and 1/8 inches.
Return the automatic choke valve to its factory specification by first loosening the choke's cover, located on the passenger's side of the carburetor, with a screwdriver. Turn the choke cover to the "1 Rich" mark stamped into the cover.
