Engine And Tune-Up Specifications; Mcm (Sterndrive) - Mercury MerCruiser MCM 4.3L ALPHA Service Manual

SERVICE MANUAL NUMBER 25

Engine and Tune-Up Specifications

MCM (Sterndrive)

Propshaft Horsepower
(SAV1 Rating)
Propshaft Kilowatts (SAV1 Rating)
Number of Cylinders
Displacement
Bore / Stroke - in. (mm)
Compression Ratio
Compression Pressure
Idle rpm In Neutral
Maximum rpm (at WOT)
Oil Pressure (at 2000 rpm)
Minimum Oil Pressure (at Idle)
Fuel Pressure (1800 rpm)
Electrical System
Alternator Rating
Minimum Battery Requirements
Firing Order
Spark Plug Type
Spark Plug Gap
Timing (at idle rpm)
Preliminary Idle Mixture
Thermostat
1
Power Rated in Accordance with NMMA (National Marine Manufacturers' 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" Bodensee and Swiss Regulations. Horsepower differences shown result from
differences in test rpm, allowable test tolerances, and/or installation of special kit components.
3
Measured using an 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. Timing can-
not be properly set using the conventional method.
5
A special procedure must be followed to adjust idle rpm. Consult your Authorized Mercury MerCruiser Dealer
before attempting this procedure.
6
Idle speed on EFI models is not adjustable.
7
Minimum recorded compression in any one cylinder should not be less than 70 percent of the highest recorded
cylinder.
8
Serial Number Break for 65 Amp alternator: OL619083 and above.
Index
90-861328--1 NOVEMBER 1999
Model
3
3
4
MCM 4.3L MCM 4.3LH
ALPHA / ALPHA /
BRAVO BRAVO
190 205 (190)
142 153 (142)
V-6
262 cid (4.3 l)
4.0 x 3.48 (101.6 x 88.4)
9.4:1
Minimum 100 psi (690 kPa)
5
650 rpm
4400-4800 rpm
Minimum 30 psi (207 kPa)
Minimum 4 psi (28 kPa)
3-7 psi (21-48 kPa)
12 V Negative (–) Ground
55 or 65 amp
375 cca / 475 mca / 90 Ah
1-6-5-4-3-2
AC - MR43LTS
Champion - RS12YC
NGK - BPR6EFS
.045 in. (1.1 mm)
10° BTDC
1 1/4 Turns
160° F (71° C)
MAINTENANCE
MCM 4.3L
EFI
ALPHA /
BRAVO
2 1
210 (188)2
2 1 2
157 (146)
9.4:1
7
5
600 rpm
30 psi ( kPa)
8
8° BTDC
DNA
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