Page 240 - REPOWER REFERENCE GUIDE (2020)

Single Catalyst V8 Engines
Oxygen Sensor

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NOTE: Refer to the appropriate exploded view for oxygen sensor location.
Removal

! CAUTION
A hot oxygen sensor can cause burns. Do not touch the sensor without first allowing it to cool. Always allow engine
components time to reach a safe temperature before installing or servicing engine or drive components.
1. Disconnect the sensor from the engine harness.
2. Loosen the screw securing the oxygen sensor cover bracket, and remove the cover bracket.
3. Remove the oxygen sensors, as needed.
7/8 in. Oxygen Sensor Socket Obtain locally
Installation

1. Use the oxygen sensor tool to install the oxygen sensor. Tighten the sensor to the specified torque.
7/8 in. Oxygen Sensor Socket Obtain locally

Description Nm lb‑in. lb‑ft
Oxygen sensor 50 – 36.9
2. Install the oxygen sensor cover bracket. Tighten the screw to the specified torque.
Description Nm lb‑in. lb‑ft
Oxygen sensor cover bracket screw 3 26.6 –
3. Connect the sensor to the engine harness.
Exhaust Manifold Coolant Temperature (EMCT) Sensor
NOTE: The exhaust manifold coolant temperature (EMCT) sensor is a thermistor that is screwed into the exhaust elbow. Refer
to the appropriate exploded view for EMCT sensor location.
Removal
1. Disconnect the EMCT sensor connector from the engine harness.
2. Remove the EMCT sensor from the exhaust elbow.
Installation
1. Verify that the O‑ring is on the EMCT sensor.

a a - EMCT sensor connector

b b - EMCT sensor
c - O‑ring

c

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2. Hand‑start the EMCT sensor into the exhaust elbow.

Page 7E-24 © 2019 Mercury Marine 90-8M0149179 eng NOVEMBER 2018