TOHATSU MD 70-90C2 Service Manual page 154

Power Unit
3. Inspection of Piston Rings
1) Push a piston ring into the cylinder by using top surface
of a piston.
2) Use thickness gauge to measure piston ring gap.
Replace piston ring if the gap is over specified value.
Thickness Gauge :
Commercially Available Item
Piston Ring End Gap : Standard Value
Top Ring
Second Ring
Third Ring
Functional Limit :
a Top Ring
b Second Ring
c Third Ring
4. Inspection of Piston Ring Side Clearance
1) Attach a piston ring to piston, and measure piston ring
side clearance. Replace piston ring if the clearance is
over specified value.
Piston Ring Tool :
P/N. 353-72249-0
Piston Ring Side Clearance :
Standard Value :
Top Ring
Second Ring
Third Ring
Functional Limit :
a Top Ring
b Second Ring
c Third Ring
5-38
}
0.25 - 0.40 mm
(0.0098 - 0.0157 in)
}
0.8 mm
(0.0315 in)
}
0.04 - 0.08 mm
(0.0016 - 0.0032 in)
}
0.10 mm
(0.0039 in)
c
b
a
TLDI 75/90C2 2010