Mercury MerCruiser MCM 454 Mag MPI Service Manual page 25

MAINTENANCE
Tune-Up Specifications
MCM (Sterndrive) Models
Propshaft Horsepower
(SAV1 Rating)
Propshaft Kilowatts
(SAV1 Rating)
Number of Cylinders
Displacement
Bore/Stroke In. (mm)
Compression Ratio
Compression Pressure
Idle rpm (in Forward Gear)
Max. rpm (at W.O.T.)
Oil Pressure (at 2000 rpm)
Min. Oil Pressure (at Idle)
Electrical System
Fuel Pressure (Running)
Min. Battery Requirements
Firing Order
Spark Plug Type
Spark Plug Gap
Timing (at Idle rpm)
Thermostat
1
Power rated in accordance with NMMA (National Marine Manufacturer's Association) rating procedures.
2
Power rated in accordance with SAV1 rating procedures. This rating procedure is used to certify that the engine
complies with "Stage 1" Swiss Regulations. Horsepower differences shown result from differences in test rpm,
allowable test tolerances, and/or installation of special kit components.
3
Measured using a accurate service tachometer with engine at normal operating temperature.
4
Timing must be set using a special procedure as outlined in the appropriate section of this manual.
5
Idle speed on EFI engines is not adjustable.
6
Minimum recorded compression in any one cylinder should not be less than 70 percent of the highest recorded
cylinder.
Index Index
Page 1B-8
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Model MCM 7.4L MPI
5
AC MR43LTS
NGK BPR6EFS
MCM 454 Mag
MPI
1
310
385
2
(275 )
1
231
287
2
(205 )
8
454 C.I.D (7.4L)
4.25 x 4.00 (108 x 101.6)
9.3:1 8.6:1
Minimum 100 psi (690 kPa)
600
3
4200-4600
Minimum 30 psi (207 kPa)
Minimum 4 psi (28 kPa)
12 V Negative (–) Ground
43 psi (248 kPa)
650 cca / 825 mca / 150Ah
1-8-4-3-6-5-7-2
Champion
Champion RV15YC4
RV12YC
.045 in.
(1.1 mm)
8 BTDC
160 F (71 C)
SERVICE MANUAL NUMBER 23
MCM 502 Mag
MPI
1 1
415
1 1
309
502 C.I.D.
(8.2L)
4.47 x 4.00
(113.5 x 101.6)
8.75:1
6
3
3
4600-5000
AC MR43T
NGK BR6FS
.040 in. (1 mm)
4
90-861326--1 MARCH 1999