Engine Temperature Coolant Sensor (Etc); Etc Removal And Installation - Mercury 25 EFI Service Manual

Ignition
6. Measure the resistance of the spark plug cap. Replace the spark plug cap if not within specifications.
a
High tension lead end
7. Reinstall the spark plug cap onto the spark plug high tension lead.

Engine Temperature Coolant Sensor (ETC)

The engine temperature coolant sensor is located on the top of the cylinder block. The ETC sensor monitors the temperature of
the cooling water that has passed through the engine as controlled by the thermostat. The ECM monitors the engine
temperature through the ETC sensor and adjusts the amount of fuel injected into the combustion chamber to achieve optimum
fuel economy based on the engines RPM.
In the event of an over‑temperature exceeding 90 °C (194 °F), the ECM will limit engine power, generate a failure code, and
complete the circuit for the warning horn and low oil pressure lamp; informing the operator of potential engine damage.

ETC Removal and Installation

ETC Removal
1. Remove the recoil assembly and the timing belt cover. Refer to Section 8 ‑ Recoil Starter.
2. Disconnect the engine wire harness connector from the ETC sensor.
3. Unthread the ETC sensor from the cylinder block.
b
a
ETC Installation
1. Cover the threads of the ETC sensor with Loctite 567 PST Pipe Sealant.
2. Thread the ETC sensor into the cylinder block. Tighten the ETC sensor to the specified torque.
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b
c
9955
Meter Test Leads
Red
© 2016 Mercury Marine
a - Meter negative lead
b - Spark plug cap
c - Meter positive lead
Black
Spark plug end
c a - Fuel cooler
b - ETC sensor
c - Engine wire harness connector
11580
Meter Scale Reading (Ω)
Auto range 3.0k ‑ 7.0k
90-8M0105568 eng MARCH 2016