🔍 Key Concepts

• Location and routing of fuel lines versus lube oil lines on a slow-speed diesel • Difference between high-pressure lines (from pumps to injectors) and low-pressure supply/return lines • Visual clues in the illustration: line diameter, wall thickness, and connection points at the fuel pump and cylinder cover

💭 Think About

• Trace where line E starts and ends in the drawing—does it connect to the fuel pump, the injector, or to a lube oil manifold? • Compare the thickness and apparent robustness of line E with other lines shown; which systems normally require the strongest piping on a slow-speed main engine? • Ask yourself at what pressure fuel is delivered to the injector on a slow-speed diesel, and whether a low‑pressure pipe could safely do that job

✅ Before You Answer

• Verify whether line E runs from the fuel pump block (labeled nearby) toward the cylinder/head area where the injector would be located • Confirm that typical high-pressure fuel lines are short, rigid, and have heavy fittings, while lube oil lines are often smaller and may connect to bearings or cooling passages • Before choosing, be sure you can explain to yourself why that line must be either fuel or lube oil, and why it must be high or low pressure, based on its function and destination