Trim "In" Angle Adjustment - Mercury 40 FourStroke Service Manual

GENERAL INFORMATION
4. Increase steering torque or pull to the left at a normal installation height (with the normal
right hand rotation propeller).
5. In excess, cause boat "porpoising" (bouncing) or propeller ventilation.
6. Cause engine overheating if any water intake holes are above the water line.

Trim "In" Angle Adjustment

Some outboard boats, particularly some bass boats, are built with a greater than normal
transom angle which will allow the outboard to be trimmed further "in" or "under". This great-
er trim "under" capability is desirable to improve acceleration, reduce the angle and time
spent in a bow high boat during planing off, and in some cases, may be necessary to plane
off a boat with aft live wells, given the variety of available propellers and height range of en-
gine installations.
However, once on plane, the engine should be trimmed to a more intermediate position to
a avoid a bow-down planing condition called "plowing". Plowing can cause "bow steering"
or "over steering" and inefficiently consumes horsepower. In this condition, if attempting a
turn or encountering a diagonal, moderate wake, a more abrupt turn than intended may re-
sult.
In rare circumstances, the owner may decide to limit the trim in. This can be accomplished
by repositioning the tilt stop pins into whatever adjustment holes in the transom brackets
is desired.
Avoid possible serious injury or death. Adjust outboard to an intermediate trim po-
sition as soon as boat is on plane to avoid possible ejection due to boat spin-out.
Do not attempt to turn boat when on plane if outboard is trimmed extremely in or
down and there is a pull on the steering wheel or tiller handle.
If an adjustment is required, purchase a stainless steel tilt pin (P/N 17-49930A1) and insert
it through whatever pin hole is desired. The non-stainless steel shipping bolt should not be
used in this application other than on a temporary basis.
Page 1C-16
a - Optional Tilt Pin
WARNING
a
90-857046R1 NOVEMBER 2001