MTC Marine Technician Electrical & Electronics 5

Question 1

What is the purpose of a marine battery combiner (ACR — Automatic Combining Relay)?

Accepted Answer

To automatically connect house and start batteries in parallel when either is being charged

Answer

An ACR closes when it senses charging voltage, combining battery banks to accept charge, and opens when voltage drops to prevent cross-discharge.

Question 2

On a marine diesel engine's electronic fuel injection system, the common rail stores fuel at pressures typically ranging from:

Accepted Answer

5,000–30,000 PSI

Answer

Common rail diesel systems maintain fuel at extremely high pressures (5,000–30,000+ PSI) to enable precise, multi-event injection through solenoid-controlled injectors.

Question 3

Which condition would cause a marine GPS chartplotter to display an 'HDOP HIGH' warning?

Accepted Answer

Available satellites are clustered in one area of the sky, reducing geometric accuracy

Answer

HDOP (Horizontal Dilution of Precision) is high when visible GPS satellites have poor geometric spread, reducing the accuracy of position calculations.

Question 4

A marine technician is diagnosing an engine that cranks but won't start. The CKP (crankshaft position sensor) signal is absent on a scan tool. This most directly affects:

Accepted Answer

The ECM's ability to determine crank position for spark and injection timing

Answer

Without a CKP signal, the ECM cannot determine piston position, preventing it from triggering spark events and fuel injection at the correct crank angle.

Question 5

In marine electrical systems, a 'bonding system' connects all underwater metal components to:

Accepted Answer

A common negative conductor that terminates at the sacrificial anode system

Answer

The bonding system equalizes electrical potential between underwater metals, directing any galvanic current through sacrificial zinc anodes rather than through the metals themselves.

(MTC) Marine Technician Certification Practice Test

(MTC) Marine Technician Certification Practice Test

MTC Marine Technician Electrical & Electronics 5