SELVA MARINE Fin Whale 225 EFI, Service Manual

Page: 152 / 399

POWR
Power unit
5-51
6AL3J11
8. If the valve seat contact width 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.
b
Previous contact width
9. If the valve seat contact width is too nar-
row and situated near the bottom edge of
the valve face, use a 60
° cutter to cut the
bottom edge of the valve seat. If neces-
sary, use a 45
° cutter to center the area
and set its width.
b
Previous contact width
10. After refacing the valve seat to the speci-
fied contact width, apply a thin, even
layer of lapping compound onto the valve
seat, and then lap the valve using a valve
lapper (commercially available).
CAUTION:
Do not get the lapping compound on the
valve stem and valve guide.
11. After every lapping procedure, be sure to
clean off any remaining lapping com-
pound from the cylinder heads and the
valves.
12. Check the valve seat contact area of the
valve again.
NOTE:
To check the valve seat contact area, see
Chapter 5,
“ Checking the valve seat. ”
Checking the cylinder head
1. Eliminate carbon deposits from the com-
bustion chambers and check for deterio-
ration.
2. Check the cylinder head warpage using a
straightedge
1
and thickness gauge
2
in the directions shown. Replace the cyl-
inder head assembly if above specifica-
tion.