MerCruiser MCM 3.0LX User Manual

MAINTENANCE - 1B - 390-816462 2-695
Tune-Up Specifications
Model MCM 3.0L MCM 3.0LX
Propshaft Horsepower Ratings
(Kilowatts)
115 (86) 135 (101)
Number Of Cylinders 4
Displacement 181 CID (3.0L)
Bore/Stroke 4.00 in./3.60 in. (101.6/91.4 mm)
Compression Ratio 9.25:1
Compression Pressure 140 PSI (966 kPa)
Idle RPM (in Forward Gear) 650-700
Maximum RPM (at W.O.T.) 4200-4600 4400-4800
OIl Pressure (at 2000 RPM) 30-60 PSI (207-414 kPa)
Min. Oil Pressure (at Idle) 5 - 6-1/2 PSI (35-44 kPa)
Fuel (Pump) Pressure 12 Volt Negative (–) Ground
Min. Battery Cold
Cranking Amperes
375 cca / 475 mca / 90 Ah
Firing Order 1-3-4-2
Spark Plug Type
AC-MR43T
Champion RV15YC4
NGK BR6FS
AC-MR43LTS
Champion RS9YC
NGK BPR6EFS
Spark Plug Gap .035 In. (0.9 mm)
Ti i ( Idl RPM)
Breaker Points Ignition 8° BTDC
Timing (at Idle RPM) DDIS Ignition 8° BTDC
Delco EST Ignition 1° BTDC (NOTE)
Preliminary Idle Mixture 1 -1/4 Turns
Thermostat 143°F (62° C)
Dwell 39° - 45°
Breaker Point Gap .016 in. (0.5 mm)
Breaker Point Spring Tension 20-27 oz. (567 - 765 g)
NOTE: Timing must be set using a special procedure as outlined in the appropriate Service Manual. Timing cannot
be properly set using the conventional method.
L.H. ROTATION FIRING ORDER
FRONT
50653
1-3-4-2
Engine Firing Order
Index

MerCruiser MCM 3.0LX Specifications

General

Displacement	181 CID (3.0L)
Horsepower	135 HP
Fuel System	Carbureted
Ignition	Electronic
Alternator	65 Amp
Cylinders	4
Aspiration	Naturally Aspirated
Horsepower @ RPM	135 HP @ 4800 RPM
Full Throttle RPM Range	4400-4800 RPM
Fuel Type	Gasoline
Cooling System	Raw Water Cooled
Oil Capacity	4.5 Quarts
Bore x Stroke	4.00 x 3.60 in. (101.6 x 91.4 mm)
Dry Weight	635 lbs