Tachometer; Gauge Replacement - Mercury MerCruiser MCM 454 Mag MPI Service Manual

INSTRUMENTATION
CALIBRATION CHART

Tachometer

TESTING
1. Connect a service tachometer to engine and compare readings.
2. Replace if not within specifications.

Gauge Replacement

1. Disconnect battery cables from battery.
2. Remove wires from back of gauge.
3. Remove hoses (vacuum, speedometer gauge).
4. Disconnect light socket.
5. Remove holding strap and remove gauge.
6. Position gauge assembly in appropriate mounting hole.
7. Install holding strap and nuts. Tighten nuts evenly and securely.
IMPORTANT: Do not distort case or bracket by overtightening.
8. Connect ground (BLACK) wire to ground terminal, if gauge is not mounted in metal
panel.
9. Connect other wires to gauge as shown in SECTION 4E.
10. Connect hoses (vacuum, speedometer gauges).
11. Install gauge light socket.
12. Coat all terminals with Quicksilver Liquid Neoprene.
13. Reconnect battery cables to battery.
Index
Page 4D-8
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Air Pressure Gauge psi
5.3
27.8
Tachometer
6000 rpm
8000 rpm
SERVICE MANUAL NUMBER 23
Speedometer Gauge MPH (km/Hr)
20 2 (32 1.6)
45 1 (72 1.6)
Allowance
150 rpm
200 rpm
90-861326--1 MARCH 1999