What Is Under My Injector?

The components that are located under the Yanmar "YM Series" injector are shown below. Yanmar uses what is called "indirect Injection" where the fuel is not injected directly into the cylinders. Instead, the fuel is shot into a smaller cavity. These smaller cavities (pre-combustion chambers) are where the actual combustion explosion starts and then spreads out into the cylinder. The lower chamber (44) has a small nozzle that is pointed a specific direction and has a small roll pin in the side so that it can only be installed one way. 

Injector Retainer (48)
Injector (18)
Insulator Washer (47)
Upper Pre-Chamber (45)
Copper Sealing Washer (46)
Lower Pre-Chamber (44)
Copper Sealing Washer (46)