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

To prevent batteries from discharging below a set voltage

Answer

To convert 24V systems to 12V for accessories

Answer

To balance charge between AGM and flooded batteries

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

100–300 PSI

Answer

500–1,000 PSI

Answer

50–75 PSI

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

The antenna cable has high resistance

Answer

The chart card is corrupted

Answer

Shore power is interfering with the GPS receiver

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

Fuel pump prime pressure only

Answer

Idle speed control and throttle response

Answer

Transmission shift scheduling

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 positive battery terminal

Answer

The shore power ground wire only

Answer

Each other and the DC negative bus, isolated from shore ground

Question 6

What marine electronics standard defines the sentence format '$GPRMC' and similar GPS data strings?

Accepted Answer

NMEA 0183

Answer

NMEA 2000 (N2K)

Answer

SeaTalk proprietary protocol

Answer

J1939 marine profile

Question 7

When an outboard engine's TPS (Throttle Position Sensor) fails and reads maximum throttle at idle, the most likely symptom is:

Accepted Answer

Engine runs at maximum RPM regardless of throttle input

Answer

Engine cranks but will not fire

Answer

Engine misfires only at high RPM

Answer

Fuel pump fails to prime