BRP Johnson 4HP Service Manual page 97

Identification of oversize piston / piston ring
Two oversize piston / piston ring components, 0.25 mm and
0.50 mm, are available.
Oversize piston / piston ring are marked as shown in the fig-
ures.
Piston
Oversize
0.25 mm
0.50 mm
1st ring and 2nd ring
Oversize
0.25 mm
0.50 mm
Oil ring
Oversize
0.25 mm
0.50 mm
NOTE:
For the oil ring side rail, measure the outer diameter of the
rail in order to distinguish because there is no I.D. mark.
I.D. mark
0.25
0.50
I.D. mark
25
50
I.D. mark
White paint
Blue paint
CYLINDER / PISTON / PISTON RING
I.D. mark
1st, 2nd, ring
I.D. mark
Oil ring spacer
POWERHEAD
I.D. mark
6-23