Coast Guard Exams
Question 150Motor Plants - QMED70% to pass

Fuel injection pumps using the port and helix metering principle requires the use of a _______________.

AI Explanation
The correct answer is B) lapped plunger and barrel. Fuel injection pumps using the port and helix metering principle require a lapped plunger and barrel design to precisely control the fuel delivery. The lapped surfaces between the plunger and barrel allow for a tight, leak-free fit that enables the accurate metering of fuel through the ports and helical grooves. This design is essential for the proper operation of port and helix fuel injection systems. The other options are incorrect because: A) crosshatched design is not specifically required for port and helix fuel injection pumps, C) variable stroke is not a necessary feature, and D) variable cam lift is not relevant to the fuel injection pump itself.

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