SERVICE STANDARDS
Service Standards
14-4
6LY3 Service Manual
© 2007 Yanmar Marine International
Cylinder Head
General
Intake / Exhaust Valve and Guide
Valve Spring
Rocker Arm and Shaft
Inspection Item
Standard
Limit
Reference Page
Combustion Surface Distortion
0.05 mm or less
(0.0019 in.)
0.20 mm
(0.0078 in.)
5-29
Valve Sink
Intake
0.7-0.9 mm
(0.0275-0.0354 in.)
1.2 mm
(0.0472 in.)
5-29
Exhaust
1.2-1.4 mm
(0.0472-0.0551 in.)
1.7 mm
(0.0669 in.)
Valve Seat Angle
Intake
90°C (194°F)
—
5-29
Exhaust
90°C (194°F)
—
Inspection Item
Standard
Limit
Reference Page
Intake
Guide Inside Diameter
8.010-8.025 mm
(0.3153-0.3159 in.)
8.1 mm
(0.3188 in.)
5-30
Valve Stem Outside
Diameter
7.960-7.975 mm
(0.3133-0.3139 in.)
7.90 mm
(0.3110 in.)
Clearance
0.035-0.065 mm
(0.0013-0.0025 in.)
0.18 mm
(0.0070 in.)
Exhaust
Guide Inside Diameter
8.015-8.030 mm
(0.3155-0.3161 in.)
8.1 mm
(0.3188 in.)
Valve Stem Outside
Diameter
7.955-7.970 mm
(0.3131-0.3137 in.)
7.90 mm
(0.3110 in.)
Clearance
0.045-0.075 mm
(0.0017-0.0029 in.)
0.18 mm
(0.0070 in.)
Valve Guide
Projection
Intake
9.0-9.5 mm
(0.3543-0.3740 in.)
—
5-32
Exhaust
7.0-7.5 mm
(0.2755-0.2952 in.)
—
Valve Guide Installation Method
Cold-fitted
—
Inspection Item
Standard
Limit
Reference Page
Free Length (Intake / Exhaust)
53.0 mm
(2.0866 in.)
51.5 mm
(2.0275 in.)
5-32
Inclination (Intake / Exhaust)
—
1.2 mm
(0.0472 in.)
Inspection Item
Standard
Limit
Reference Page
Arm Shaft Hole Diameter
20.000-20.020 mm
(0.7873-0.7881 in.)
20.090 mm
(0.7909 in.)
5-35
Shaft Outside Diameter
19.970-19.990 mm
(0.7862-0.7870 in.)
19.955 mm
(0.7856 in.)
Clearance
0.010-0.050 mm
(0.0003-0.0019 in.)
0.140 mm
(0.0055 in.)