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
This conﬁguration allows the engine to operate
within the recommended rpm range with a heavy
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 overtrimming in the future.
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.
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-
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.
Trimming out, in addition to raising the bow, also
lifts the boat higher, gaining speed because less
hull is in the water.
B. Tilt/Trim Control Switches
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: 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.
The standard trim control switch is located on the
control lever handle.
The switch controls the position of the stern drive.
Proper trim is very important in boating.
NOTE: Refer to the control instructions regarding the
power trim controls installed on your boat.
In the case of low or heavy bow attitude, the boat
tends to “plow” (Figure T-3. The lower unit is
trimmed too far under or forward. Trim the unit UP
(out) to correct this situation.
If the bow is too high, the boat tends to “porpoise”
(Figure T-5). The drive unit is trimmed up or out
too far. Trim DN (in) to correct.
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.
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
Figures T-3-T-5: Trimming the Boat with Outdrive
Prelaunch and Underway - Section T
Owner’s Manual Page 138
|Categories||Four Winns F-Series Manuals, Four Winns Manuals|
|Tags||Four Winns F|
|Document Type||Owner's Manual|
|Product Brand||Boats and Cruisers, Four Winns. For support contact your dealer at http://www.fourwinns.com/locate-dealer.aspx|
|Document File Type|
|Wikipedia's Page||Outboard Marine Corporation|
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