Yanmar 3JH3E Service Manual page 27

Chapter 2 Basic Engine
_3_.
_P_is_t_on_s_a_n_d_P_i_s_to_n_._P_in_s ________________________
3,4]H3(B)(C)E
3-1 Piston
3-1.1 Piston head and combustion surface
Remove the carbon that has accumulated on the piston
head and combustion surface, taking care not to scratch
the piston. Check the combustion surface for any damage.
3-1.2 Measurement of piston outside diameter/
inspection
{1) Replace the piston
it
the outsides of the piston or ring
grooves are worn.
(2) Measure the piston 22mm from the bottom at right
angles
to the piston pin.
Standard
Wearlfmit
83.945~83.975 83.90
2-12
3-1.3 Replacing the piston
A floating type piston pin is used in this engine. The
piston pin can be pressed into the piston pin hole at
room temperature {coat with oil to make it slide in
easily).
0
3·2 Piston pin
Measure the outer diameter and replace the pin if
it
is
excessively worn.
Standard
Piston pin insert
hole dia.
,f,
26.000~26.009
Piston pin
outside dia.
¢ 25987~26.000
Standard clearance 0~0.022
mm
Wear
limit
1'26.020
¢25.900
0.12
Printed in Japan
HINSHI-H8009