Johnson J2R4SUC 2007, Service Manual

Page: 77 / 179

POWERHEAD
SPECIFICATIONS
75
6
Item Unit
Data
2.5 HP
CYLINDER / PISTON / PISTON RING
Cylinder distortion Limit mm (in) 0.05 (0.002)
Piston to cylinder
clearance STD mm (in) 0.018 – 0.033 (0.0007 – 0.0013)
Limit mm (in) 0.100 (0.0039)
Cylinder bore STD mm (in) 48.000 – 48.015 (1.8898 – 1.8904)
Cylinder measuring position mm (in) 20 (0.8) from cylinder top surface
Piston skirt diameter STD mm (in) 47.975 – 47.990 (1.8888 – 1.8894)
Piston measuring position mm (in) 5 (0.2) from piston skirt end
Cylinder bore wear Limit mm (in) 0.100 (0.0039)
Piston ring end
gap
1st,
2nd
STD mm (in) 0.15 – 0.35 (0.006 – 0.014)
Limit mm (in) 0.50 (0.020)
Piston ring free
end gap
1st
STD mm (in) Approximately 6.1 (0.24)
Limit mm (in) 4.9 (0.19)
2nd
STD mm (in) Approx. 5.7 (0.22)
Limit mm (in) 4.6 (0.18)
Piston ring to
groove
clearance
1st,
2nd
STD mm (in) 0.020 – 0.060 (0.0008 – 0.0024)
Limit mm (in) 0.120 (0.0047)
Piston ring
groove width 1st,
2nd
STD mm (in) 1.21 – 1.23 (0.048 – 0.049)
Pin clearance in piston
pin hole STD mm (in) 0.002 – 0.013 (0.0001 – 0.0005)
Limit mm (in) 0.040 (0.0016)
Piston pin outside
diameter STD mm (in) 11.995 – 12.000 (0.4722 – 0.4724)
Limit mm (in) 11.980 (0.4717)
Piston pin hole diameter STD mm (in) 12.002 – 12.008 (0.4725 – 0.4728)
Limit mm (in) 12.030 (0.4736)
Pin clearance in
connecting rod small end STD mm (in) 0.006 – 0.019 (0.0002 – 0.0007)
Limit mm (in) 0.050 (0.0020)
CRANKSHAFT / CONNECTING ROD
Connecting rod small
end inside diameter STD mm (in) 12.006 – 12.014 (0.4727 – 0.4730)
Limit mm (in) 12.040 (0.4740)
Connecting rod big end
oil clearance STD mm (in) 0.015 – 0.035 (0.0006 – 0.0014)
Limit mm (in) 0.080 (0.0031)
Connecting rod big end
inside diameter
STD mm (in) 19.015 – 19.025 (0.7486 – 0.7490)
Crank pin outside
diameter
STD mm (in) 18.990 – 19.000 (0.7476 – 0.7480)
Crank pin outside diame-
ter difference (out-of-
round and taper)
Limit mm (in) 0.010 (0.0004)
Connecting rod big end
side clearance STD mm (in) 0.20 – 0.70 (0.008 – 0.028)
Limit mm (in) 1.00 (0.039)
Connecting rod big end
width
STD mm (in) 17.50 – 17.80 (0.689 – 0.701)
Crank pin width STD mm (in) 18.00 – 18.20 (0.709 – 0.717)
Crankshaft runout Limit mm (in) 0.05 (0.002)