The uninspected fishing vessel to which you are assigned has a deck winch drive engine fitted with fuel injectors with the operating principle as shown in the illustration. In figure "A" which plunger travel position corresponds to when fuel injection ends? Illustration MO-0144
• Study how the upper port, lower port, and recessed/helix area line up with the barrel in each vertical position 1–4 in Figure A. • Remember that injection begins when the spill (horizontal) port is closed and high pressure can build above the plunger. • Injection ends when a port is uncovered again, allowing fuel to spill off and pressure at the nozzle to drop.
• In Figure A, at which numbered position is the plunger’s recessed/helix area first opening a passage back to the port so pressure can no longer be maintained at the nozzle? • Compare positions 2, 3, and 4: in which one is there a clear flow path from the high‑pressure area above the plunger back to a port, so the pump can no longer deliver fuel? • Ask yourself: if the plunger kept moving downward past the end‑of‑injection point, would that change the fact that the ports are already uncovered and pressure has collapsed?
• Identify in each position whether the horizontal drilling/port is covered or uncovered by solid plunger metal. • Confirm where the recessed/helix area connects the high‑pressure side to the port – that position corresponds to the end of injection. • Make sure you are looking only at Figure A (vertical plunger travel) and not the rotational positions in Figure B when choosing among 1–4.
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