SELVA MARINE Blue Whale 250 EFI, Service Manual

Page: 160 / 377

POWR
Power unit
5-47
6P23H11
2. Cut the surface of the valve seat with a
45
° cutter by turning the cutter clockwise
until the valve seat face has become
smooth.
a
Slag or rough surface
CAUTION:
Do not over cut the valve seat. Be sure to
turn the cutter evenly downward at a pres-
sure of 40
– 50 N (4 – 5 kgf, 8.8 – 11 lbf) to
prevent chatter marks.
3. Use a 30 ° cutter to adjust the contact
width of the top edge of the valve seat.
b
Previous contact width
4. Use a 60 ° cutter to adjust the contact
width of the bottom edge of the valve
seat.
b
Previous contact width
5. Use a 45 ° cutter to adjust the contact
width of the valve seat to specification.
b
Previous contact width
c
Specified contact width
6. If the valve seat contact area is too wide
and situated in the center of the valve
face, use a 30
° cutter to cut the top edge
of the valve seat, a 60 ° cutter to cut the
bottom edge to center the area and set
its width.
b
Previous contact width
7. If the valve seat contact area is too nar-
row and situated near the top edge of the
valve face, use a 30
° cutter to cut the top
edge of the valve seat. If necessary, use
a 45
° cutter to center the area and set its
width.
È
S69J5880
30˚
b
S69J5890
60˚
b
S69J5900
45˚
b
c