Oxygen Sensor - Mercury MerCruiser Service Manual

10. If installing the port exhaust manifold, install the O2 sensors.
a
ECT model
a - Port postcatalyst O2 sensor (ECT models only)
b - Port precatalyst O2 sensor (all models)
7/8 in. Oxygen Sensor Socket
Description

Oxygen sensor

11. If installing the starboard exhaust manifold, install the O2 sensors, and attach the shift plate, using the three mounting
screws.
d
c
a
Description
Oxygen sensor
12. Fill the closed‑cooling system, if equipped, with the recommended coolant/antifreeze.
13. Connect both battery cables. Be certain to connect the negative (–) cable last.
14. Upon starting the engine, inspect all exhaust and cooling hose connections for leaks.
Oxygen Sensor
NOTE: Refer to the appropriate exploded view for oxygen sensor location.
90-8M0099748 eng DECEMBER 2015
c c
© 2016 Mercury Marine
b
56905
obtain locally
Nm
50
ECT model
a - Starboard precatalyst O2 sensor (all
b
models)
b - Starboard postcatalyst O2 sensor
(ECT models only)
c - Mounting screws (two shown, one
hidden)
d - Power steering reservoir bracket
56904
Nm
50
51233
Manifolds and Elbows
lb‑in. lb‑ft
– 36.8
lb‑in. lb‑ft
– 36.8
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