Mercury Optimax 150 User Manual

4
A
POWERHEAD
90-855347R1 JANUARY 1999 Page 4A-1
POWERHEAD
Section 4A
Table of Contents
Powerhead Specifications 4A-1. . . . . . . . . . . . . . . . . . . . .
Special Tools 4A-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Powerhead Repair Stand 4A-3. . . . . . . . . . . . . . . . . . .
Cylinder Block and End Caps 4A-4. . . . . . . . . . . . . . . . . .
Exhaust Manifold and Exhaust Plate 4A-6. . . . . . . . . . . .
Cylinder Head 4A-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Crankshaft, Pistons and Connecting Rods 4A-10. . . . . .
Torque Sequence 4A-11. . . . . . . . . . . . . . . . . . . . . . . . . . .
General Information 4A-13. . . . . . . . . . . . . . . . . . . . . . . . .
Powerhead Removal from Driveshaft Housing 4A-13. .
Powerhead Disassembly 4A-17. . . . . . . . . . . . . . . . . . . . .
Water Pressure Relief Valve Components 4A-25. . .
Torque Specifications 4A-25. . . . . . . . . . . . . . . . . . . . .
Cleaning and Inspection 4A-26. . . . . . . . . . . . . . . . . . . . . .
Cylinder Block and Crankcase Cover 4A-26. . . . . . .
Special Service Information 4A-26. . . . . . . . . . . . . . . .
Cylinder Bores 4A-27. . . . . . . . . . . . . . . . . . . . . . . . . . .
Pistons and Piston Rings 4A-28. . . . . . . . . . . . . . . . . .
Cylinder Heads and Exhaust Divider Plate 4A-30. . .
Crankshaft 4A-30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Crankshaft (and End Cap) Bearings 4A-31. . . . . . . .
Reed Block Assembly 4A-32. . . . . . . . . . . . . . . . . . . . .
End Bearing Bleed System 4A-33. . . . . . . . . . . . . . . .
Connecting Rods 4A-33. . . . . . . . . . . . . . . . . . . . . . . . .
Thermostats 4A-35. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Powerhead Reassembly and Installation 4A-36. . . . . . .
General 4A-36. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Crankshaft Installation 4A-40. . . . . . . . . . . . . . . . . . . .
Piston and Connecting Rod Reassembly 4A-42. . . .
Piston and Piston Ring Combinations 4A-43. . . . . . .
Piston Installation 4A-44. . . . . . . . . . . . . . . . . . . . . . . .
Crankcase Cover Installation 4A-46. . . . . . . . . . . . . . .
Assembly of Reed Blocks to Intake Manifold 4A-48.
Assembly of Exhaust Divider Plate to Block 4A-48. .
Reinstalling Engine Components 4A-51. . . . . . . . . . . . . .
Throttle Lever and Shift Shaft 4A-52. . . . . . . . . . . . . . . . .
Throttle Lever and Shift Shaft 4A-53. . . . . . . . . . . . . . . . .
Powerhead Installation on Driveshaft Housing 4A-54. .
Break-ln Procedure 4A-58. . . . . . . . . . . . . . . . . . . . . . . . . .
Powerhead Specifications
CYLINDER
BLOCK
Type
Displacement
V-6 Cylinder, Two Cycle, Direct Injected
153 cu. in. (2508 cc) 60° Vee
STROKE Length (All Models) 2.65 in. (67.3 mm)
CYLINDER
BORE
Diameter (Std)
Diameter 0.015 in. Oversize
Taper/Out of Round/Wear Maximum
Bore Type
3.501 in. (88.925 mm)
3.516 in. (89.306 mm)
0.003 in. (0.076 mm)
Cast Iron
PISTON Piston Type
Diameter Standard
Diameter 0.015 in. Oversize
Aluminum
3.4925 in. ± .0005 in.
(88.7095 mm ± 0.0127 mm)
3.5075 in. ± 0.0005 in.
(89.0905 mm ± 0.0127 mm)
CRANKSHAFT Maximum Runout 0.006 in. (0.152 mm)

Mercury Optimax 150 Specifications

General

Horsepower	150 HP
Engine Type	V6
Alternator Output	60 amp / 756 watt
Starting	Electric
Steering	Remote
Displacement	2.5 L
Fuel Induction System	2-Stage Direct Fuel Injection (DFI)
Shaft Length	20", 25"
Dry Weight	431 lbs (20 in), 439 lbs (25 in)