MAINTENANCE
SERVICE MANUAL NUMBER 23
Page 1B-8
90-861326--1 MARCH 1999
Tune-Up Specifications
MCM (Sterndrive) Models
Model
MCM 7.4L MPI
MCM 454 Mag
MPI
MCM 502 Mag
MPI
Propshaft Horsepower
(SAV1 Rating)
310
1
(275
2
)
385
1
415
1
Propshaft Kilowatts
(SAV1 Rating)
231
1
(205
2
)
287
1
309
1
Number of Cylinders
8
Displacement
454 C.I.D (7.4L)
502 C.I.D.
(8.2L)
Bore/Stroke In. (mm)
4.25 x 4.00 (108 x 101.6)
4.47 x 4.00
(113.5 x 101.6)
Compression Ratio
9.3:1
8.6:1
8.75:1
Compression Pressure
Minimum 100 psi (690 kPa)
6
Idle rpm (in Forward Gear)
5
600
3
Max. rpm (at W.O.T.)
4200-4600
3
4600-5000
3
Oil Pressure (at 2000 rpm)
Minimum 30 psi (207 kPa)
Min. Oil Pressure (at Idle)
Minimum 4 psi (28 kPa)
Electrical System
12 V Negative (–) Ground
Fuel Pressure (Running)
43 psi (248 kPa)
Min. Battery Requirements
650 cca / 825 mca / 150Ah
Firing Order
1-8-4-3-6-5-7-2
Spark Plug Type
AC MR43LTS
Champion
RV12YC
NGK BPR6EFS
AC MR43T
Champion RV15YC4
NGK BR6FS
Spark Plug Gap
.045 in.
(1.1 mm)
.040 in. (1 mm)
Timing (at Idle rpm)
8
°
BTDC
4
Thermostat
160
°
F (71
°
C)
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.
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Index
Index
