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unit out too far, your boat will porpoise or the propel-
ler will cavitate, and the bow will slam up and down
on the water. Your boat is trimmed correctly when it is
just short of porpoising or propeller cavitation, under
ideal running conditions.
Trim your boat to compensate for seas, winds,
or uneven loads.
Head Seas
Following Seas
Listing Due to Quar-
tering Seas, Beam
Wind, or Uneven Load
Remember that most boats react very slowly to trim
tabs. Often boat owners do not give trim tabs time to
work. Press the trim tab switches for only one second
at a time and then allow some time for the boat to
react. If the boat is still listing after a minute or two,
press the trim tab switch again for a one second inter-
val. The labels on the trim tab switches indicate what
you want your boat to do, not what you want the tabs
to do.
It is a good idea to take your boat out onto open water
shortly after you get it and experiment with the trim
tabs. After you get your boat onto plane, set the tabs
in various positions and note how your boat reacts.
This will give you a feel for how the trim tabs work.
It is possible to extend the cylinder life expectancy on
your trim tabs. To do this, keep the cylinders retracted
while at dockside. Press both trim tab controls down
until tabs reach their full up position.
B. Tilt/Trim Control Switches
NOTE: Trim refers to the angle of the lower unit in
relation to the bottom of the boat. With respect to trim-
ming, the words in, down, under, and forward, have
the same meaning as do up, out, and aft.
1. The standard trim control switch is located on the
control lever handle.
Prelaunch and Underway - Section T
Trim drives in more than
usual. Use tabs to keep
bow down and move at
a slower speed.
To prevent taking sea-
water over the bow, trim
drives out and keep tabs
up to keep bow up.
Use tabs independently to
adjust for list. If listing to
starboard, press port bow
down switch. If listing to
port, press starboard bow
down switch.
2. The switch controls the position of the stern drive.
Proper trim is very important in boating.
3. In the case of low or heavy bow attitude, the
boat tends to "plow" (Figure T3. The lower unit is
trimmed too far under or forward. Trim the unit UP
(out) to correct this situation.
4. I f the bow is too high, the boat tends to "porpoise"
(Figure T5). The drive unit is trimmed up or out too
far. Trim DN (in) to correct.
5. A good practice is to get underway (especially
when fully loaded or pulling a skier) with the unit
trimmed all the way DN (under). After the boat is
on plane, adjust the trim out slightly to obtain the
proper bow attitude and engine speed.
6. Trim also affects propeller selection and fuel ef-
ficiency. All models should be "propped" to be in
the upper half of the maximum rpm range with the
boat lightly loaded and the drive trimmed up to
maximum.
T his configuration allows the engine to operate
within the recommended rpm range with a heavy
load.
The power unit should never be trimmed up to
a point where the propeller cavitates (or slips).
A rapid increase in engine rpm's is evidence of
cavitation. If this occurs accidentally while running
at full throttle, immediately lower the drive trim and
reduce the throttle until the slipping stops. If nec-
essary, have your dealer reset the trim limit switch
(if provided) to avoid over-trimming in the future.
If the prop slips at lower planing speeds, the drive
may be trimmed too high. Immediately lower the
drive unit until the prop grabs again to restore ef-
ficiency.
7. Trimming out, in addition to raising the bow, also
lifts the boat higher, gaining speed because less
hull is in the water.
8. The trailering position of some stern drives is
controlled by a separate switch on the dash switch
panel or throttle/shift control. Do not activate this
switch while engine is running. Doing so can se-
verely damage the lower unit and engine.
NOTE: Refer to the control instructions regarding the
power trim controls installed on your boat.
Owner's Manual Page 156
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