🔍 Key Concepts

• Relationship between match marks on rotating machinery parts and their purpose • How centrifuge bowls are secured and checked for proper tightening • Difference between marks used for fuel system timing/alignment and those on a purifier or separator

💭 Think About

• Look closely at where the two small circular marks are located in figure A compared with the edge and the dark rectangular cutouts—what might those cutouts represent on a rotating drum? • Ask yourself which of the options would typically use evenly spaced dark windows or slots around a circular rim, and which would more likely use fine pointer or line marks on a shaft or gear. • Consider which system (centrifuge, fuel pump, fuel rack, stroboscope) normally has an external rotating bowl or drum with marks that must line up when the securing ring is correctly tightened.

✅ Before You Answer

• Identify whether the large outer part in the illustration looks more like a bowl/drum casing or a pump gear/shaft. • Decide which component would logically have multiple rectangular openings or windows around the circumference. • Think about which option specifically requires confirming that a locking ring or bowl nut is correctly tightened by checking the relative position of two marks.