Mercury 90 - Leak down Check - Manual Release Valve; Leak down Check - Pilot Valve Assembly; Leaks Past Ball and Seat - Piston Assembly

90-830234R3 DECEMBER 1997 MID-SECTION - 5B-11
Leak Down Check - Pilot Valve
Assembly
1. Debris or chips between valve and seat (a), usu-
ally imbedded in rubber valve seat.
2. Pilot valve installed from non-chamfered end of
spool, results in nicked or damaged O-ring (b).
3. Nicked or deteriorated O-ring (c).
A leak path is created between the UP side of the cyl-
inder and the reservoir. The trim system will leak
down until the trim port in cylinder is covered.
b
c
a
51560
a - Valve and Seat
b - Pilot Valve O-ring
c - O-ring
Leak Down Check - Manual Release
Valve
1. Debris or chips under O-ring (a).
2. Flash from valve molding causing O-ring (a) to
not seal.
3. Nicked O-ring (a).
a
51560
a - O-ring
Leaks Past Ball and Seat - Piston
Assembly
Unit will trim to full or near full down position and then
will begin to trim up while trim switch is held in
‘‘DOWN” mode.
If trim switch is released, outboard can be pushed (by
hand) down to the point where trim UP started.
1. Inspect balls and seats in piston assembly for de-
bris or damage. Repair or replace balls/seats.
a
51143
a - Ball and Seat. Check all for debris or damage.