Mercury 40 Service Manual page 373

Tilt Up
In the up mode, as the trim rod (a) extends from the cylinder (w), the memory piston (t) clears
or uncovers the pressure relief passage. Oil from the up cavity will enter this passage and,
if required, causes the tilt relief piston (s) to open the tilt relief valve (r). This valve lowers
the amount of pressure available to lift the outboard motor. With the engine in forward gear,
and at high engine rpm, the oil pressure available will not be able to overcome the propeller
thrust, limiting the trim range to below the pressure relief orifice. When the engine rpm
decreases or if engine is not in forward gear, the oil pressure is available to extend the trim
rod (a) up into the tilt range.
a -
b -
c -
d -
e -
g -
h -
k -
m -
n -
o -
p -
q -
s -
u -
v -
w -
90-828631R3 MARCH 1999
Trim Rod
End Cap
Electric Motor
Reservoir Oil
Down Circuit Pressure Relief Valve
f - Down Circuit Pressure Operated Valve
Filter (2 shown for clarity)
Shock Return Valve
i - Up Circuit Suction Port
j - Oil Pump Gears
Down Circuit Suction Port
l - Oil Fill Cap
Shuttle Valve
Up Circuit Pressure Operated Valve
Manifold Reverse Suction Valve
Manual Release Valve
Manifold
r - Tilt Relief Valve
Tilt Relief Piston
t - Memory Piston
Shock Piston
Impact Relief Valve
Cylinder
POWER TRIM
Page 5C-11