Mercury 135 Pro XS OptiMax Manual page 145

However, once on plane, the engine should be trimmed to a
more intermediate position to avoid a bow‑down planing
condition called plowing. Plowing can cause bow steering or
oversteering and inefficiently consumes horsepower.
Stainless Steel Tilt Pin
The owner may decide to limit the trim in. This can be
accomplished by purchasing a stainless steel tilt pin from your
dealer and insert it in whatever adjustment hole in the transom
brackets is desired. A nonstainless steel shipping bolt should not
be used in this application other than on a temporary basis.
eng
OUTBOARD INSTALLATION
a
2688
a - Tilt pin (not included with engine)
Limits the down trim angle of the
power trim equipped engines, or
aids in determining the trim out
angle on non‑power trim
engines.
2749
133
17‑49930A 1