Mercury 45 Jet 50-55 - Powerhead; Specifications; Special Tools

1-4 - GENERAL INFORMATION and SPECIFICATIONS 90-817643R1 DECEMBER 1996
Powerhead
Specifications
Block
Type 3 Cylinder, 2 Cycle. . . . . . . . . . . . . . . . . . .
Displacement
50/55/60 Horsepower 51.8 cu in. (849 cc).
Cylinder Bore
Dia. Standard 2.955 in. (75.057 mm). . . . . . . . . . .
Dia. .015 in. Oversize 2.970 in. (75.438 mm). . . .
Dia. .030 in. Oversize 2.985 in. (75.819 mm). . . .
Out of Round (Max.) 0.003 in. (0.076 mm). . . . .
Taper (Max.) 0.003 in. (0.076 mm). . . . . . . . . . . .
Piston
Dia. Standard 2.950 in. (74.93 mm). . . . . . . . . . .
Dia. .015 in. Oversize 2.965 in. (75.31 mm). . . .
Dia. .030 in. Oversize 2.980 in. (75.69 mm). . . .
IMPORTANT: Measure piston skirt at right angle (90°)
to piston pin center line, 0.50 in. (12.7mm) up from bot-
tom edge of skirt.
0.50 in.
(12.7mm)
PISTON PISTON SKIRT CYLINDER BORE
SIZE DIAMETER FINISH HONE
Standard 2.950 in. 2.955 in.
Piston (74.93 mm) (75.057mm)
0.015 in. 2.965 in. 2.970 in.
(0.381 mm) (75.31 mm) (75.438 mm)
Oversize
0.030 in. 2.980 in. 2.985 in.
(0.752 mm) (75.69 mm) (75.819 mm)
Oversize
Reed Block
Reed Stop Opening (Max.) 0.020 in. . . . . . . .
(0.50 mm)
Crankshaft
Runout (Max.) 0.003 in. (0.08 mm). . . . . . . . . .
Taper (Max.) 0.003 in. (0.08 mm). . . . . . . . . . .
Firing Order 1-3-2. . . . . . . . . . . . . . . . . . . . . . . . . .
Special Tools
Description Part Number
Flywheel Holder 91–52344
Protector Cap 91-24161
Flywheel Puller 91-73687A1
Lifting Eye 91-90455
Piston Ring Expander 91-24697
Piston Pin Tool 91-74607A2
Lock Ring Installation
Tool
91-77109A1
Powerhead Stand 91-25821A1
*Torque Wrench (0–200
lb. ft.)
91-32610
*Torque Wrench (0–150
lb. in.)
91-66274
Compression Tester 91-29287
*May be Obtained Locally