🔍 Key Concepts

• Function of jerk-type fuel pumps in diesel engines • Relationship between tappet (push rod) adjustment and fuel pump plunger movement • How fuel quantity and timing are controlled in individual pump systems

💭 Think About

• Think about what actually changes when you adjust the tappet on a fuel pump: does it directly affect pressure in the cylinder, exhaust temperature, or how much fuel the pump delivers per stroke? • In a multi-cylinder engine with individual pumps, what do you want to be the same for all cylinders so that the engine runs smoothly? • Consider which of the choices is a direct result of tappet adjustment, and which are only indirect engine effects.

✅ Before You Answer

• Identify what part of the fuel pump’s action is controlled by tappet clearance and stroke. • Decide which option refers to something inside the fuel pump versus conditions inside the cylinder. • Check which item would logically need to be matched between all cylinders when using individual jerk-type fuel pumps.