All 22R carbureted engines are equipped with a mechanically operated fuel pump of diaphragm construction (some models use two different types of pump). A separate fuel filter is incorporated into the fuel line (see General Information & Maintenance for its required service). The fuel pump is located on the right side of the cylinder head.
REMOVAL & INSTALLATION
See Figure 1
- Disconnect the negative battery cable.
- Drain the radiator coolant.
- Disconnect the upper radiator hose and wire it out of the way.
- Label, disconnect and plug the three fuel lines from the fuel pump.
- Unscrew the two fuel pump retaining bolts. Remove the fuel pump, gaskets and insulator.
- Inspect the insulator for any cracks or damage. Replace if necessary.
- Place new gaskets on either side of the insulator. Insert the pump arm through the hole of the insulator/gaskets and mount on the engine. Tighten the two mounting screws.
Always use new gaskets when installing the fuel pump.
- Reconnect the fuel lines.
- Attach the upper radiator hose, then fill the system with a coolant/water mixture.
- Connect the negative battery cable.
- Start the engine and check for any leaks. Top off the cooling system.
Fuel pumps should always be tested on the vehicle. The larger line between the pump and tank is the suction side of the system and the smaller line, between the pump and carburetor is the pressure side. A leak in the pressure side would be apparent because of dripping fuel. A leak in the suction side is usually only apparent because of a reduced volume of fuel delivered to the pressure side.
- Tighten any loose line connections and look for any kinks or restrictions.
- Disconnect the fuel line at the carburetor or fuel pump. Disconnect the distributor-to-coil primary wire. Place a container at the end of the fuel line and crank the engine a few revolutions. If little or no fuel flows from the line, either the fuel pump is inoperative or the line is plugged. Blow through the lines with compressed air and try the test again. Reconnect the line.
- If fuel flows in good volume, check the fuel pump pressure to be sure.
- Attach a pressure gauge to the pressure side of the fuel line. On trucks equipped with a vapor return system, squeeze off the return hose.
- Run the engine at idle and note the reading on the gauge. Stop the engine and compare the reading with the specifications listed in the "Tune-Up Specifications'' chart. If the pump is operating properly, the pressure will be as specified and will be constant at idle speed. If pressure varies sporadically or is too high or low, the pump should be replaced.
- Remove the pressure gauge.