Inspecting The Push Rods; Inspecting The Timing Gear; Inspecting The Idler Gear - Yanmar 6LY3 series Service Manual

Inspecting the Cylinder Block and Components
12/05

Inspecting the Push Rods

• Measure the length and bend of the push rods as
shown in Figure 5-72.
Figure 5-72
(1)
Figure 5-72
1 – Feeler Gauge
• Replace if beyond the stated limits.
Push Rod Specifications
Less than 0.03 mm
Push Rod Bend
Push Rod Diameter 10 mm (0.3936 in.)

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.
Timing Gear Backlash
Standard
0.08-0.16 mm
(0.0031-0.0062 in.)
6LY3 Service Manual
0005657
Standard Limit
0.3 mm
(0.0011 in.) (0.011 in.)
—
Limit
0.25 mm
(0.0098 in.)
© 2007 Yanmar Marine International

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.
Idle Gear Specifications
Idler Shaft Diameter
Idler Gear Bushing Inside
Diameter
Oil Clearance
Figure 5-73
Figure 5-73
1 – Idler Gear
2 – Idler Gear Bearing
3 – Idler Gear Shaft
ENGINE
Standard Limit
53.950-53.975 mm 53.88 mm
(2.1240-2.1249 in.) (2.1212 in.)
54.000-54.025 mm 54.08 mm
(2.1259-2.1269 in.) (2.1291 in.)
0.025-0.075 mm 0.15 mm
(0.0009-0.0029 in.) (0.0059 in.)
(1)
(2)
(3)
0005658
5-51