ENGINE
Inspecting the Cylinder Block and Components
12/05
6LY3 Service Manual
5-51
© 2007 Yanmar Marine International
Inspecting the Push Rods
• Measure the length and bend of the push rods as
shown in Figure 5-72.
Figure 5-72
Figure 5-72
1 – Feeler Gauge
• Replace if beyond the stated limits.
Inspecting the Timing Gear
The timing gear is a helical design for quiet
operation and is specially treated for high durability.
1. Inspect the gears and replace if the teeth are
damaged or worn.
2. Measure the backlash of all gears that mesh
and replace the gears as a set if wear exceeds
the stated limit. NOTICE: If backlash is
excessive, it will not only result in excessive
noise and gear damage, but also lead to bad
valve and fuel injection timing and a decrease in
engine performance.
Inspecting the Idler Gear
The idler gear bearing is a press-fit in the gear.
• Measure the bearing (Figure 5-73, (2)) inner
diameter.
• Measure the outer diameter of the idler gear shaft
(Figure 5-73, (3)).
• Replace the bearing and / or idler gear shaft if the
oil clearance exceeds the stated limit.
Figure 5-7 3
Figure 5-73
1 – Idler Gear
2 – Idler Gear Bearing
3 – Idler Gear Shaft
Push Rod Specifications
Standard Limit
Push Rod Bend
Less than 0.03 mm
(0.0011 in.)
0.3 mm
(0.011 in.)
Push Rod Diameter 10 mm (0.3936 in.) —
Timing Gear Backlash
Standard Limit
0.08-0.16 mm
(0.0031-0.0062 in.)
0.25 mm
(0.0098 in.)
0005657
(1)
Idle Gear Specifications
Standard Limit
Idler Shaft Diameter
53.950-53.975 mm
(2.1240-2.1249 in.)
53.88 mm
(2.1212 in.)
Idler Gear Bushing Inside
Diameter
54.000-54.025 mm
(2.1259-2.1269 in.)
54.08 mm
(2.1291 in.)
Oil Clearance
0.025-0.075 mm
(0.0009-0.0029 in.)
0.15 mm
(0.0059 in.)
0005658
(1)
(2)
(3)
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