Yamaha F50D Servise Manual page 325

Disassembling the tilt cylinder
Make sure that the PTT ram is fully
extended before removing the tilt cylinder
end screw otherwise fluid can spurt out
from the unit due to internal pressure.
1. Hold the PTT unit 1 in a vise using alu-
minum plates a on both sides.
a
2. Loosen the tilt cylinder end screw 2, and
then remove it.
2
Cylinder-end screw wrench 3:
90890-06568
3. Drain the fluid.
Disassembling the trim cylinder
1. Hold the trim cylinder 1 in a vise using
aluminum plates a on both sides.
2. Loosen the trim cylinder end screw 2,
and then remove it. NOTICE: Do not
damage the check valve b when
loosening the end screw.
1
a
3
1
a
b
2
Cylinder-end screw wrench 3:
90890-06568
Checking the tilt cylinder and trim
cylinder
1. Check the inner walls of the trim cylinder
and tilt cylinder. Replace if there are
scratches.
2. Check the outer surface of the tilt piston
and free piston. Replace the PTT ram
assembly or free piston if there are
scratches.
3. Check the PTT ram. Polish with 400–600
grit sandpaper if there is light rust or
replace the PTT ram assembly if bent or
excessively corroded.
4. Check the check valve a of the trim cyl-
inder end screw. Clean if there is dirt or
residue.
PTT cylinder
2
a
3
a
9-46
0
1
2
3
4
5
6
7
8
9
10
A