gear pump and the use of a restricted fitting located at the cylinder head return fuel manifold.

4. To purge the fuel system of any air; the system is recirculator-y in operation, therefore allowing any air to be returned to the fuel tank.

Since the basic fuel system used on all Detroit diesel engines is identical as far as components used, the description of operation for one can be readily related to any other series of Detroit diesel engine (fig. 5-23).

The basic fuel system consists mainly of the following:

1. Fuel injectors.

2. Fuel pipes to and from the injectors (inlet and outlet).

3. Fuel manifolds, which are cast internally within the cylinder head. The upper manifold is the "inlet" and the lower is the "return" or "outlet." To prevent confusion, the words in and out are cast in the side of the head.

Figure 5-23. - Diagram of typical Detroit diesel fuel system.