Power Trim; Single-Engine Trim And Trailer - Mercury TDI 4.2L Manual

Section 1 - Getting to Know Your Power Package

Power Trim

Power trim allows the operator to adjust the sterndrive angle while underway to provide the ideal boat angle for varying load
and water conditions. Also, the trailering feature allows the operator to raise and lower the sterndrive for trailering, beaching,
launching, low‑speed (below 1200 RPM engine speed), and shallow water operation.
Excessive trim can cause serious injury or death at high speeds, and single‑ram trim systems do not provide a trim‑out
limiting device or trim indicator. Use caution when trimming with a single‑ram trim system and never trim out beyond the unit's
side support flanges while the boat is underway or at engine speeds above 1200 RPM.
For best performance, trim the sterndrive so that the boat bottom is at a 3–5° angle to the water.
Trimming the sterndrive up (out) can:
• Generally increase top speed
• Increase clearance over submerged objects or a shallow bottom
• Cause the boat to accelerate and plane off slower
• In excess, cause boat porpoising (bouncing) or propeller ventilation
• Cause engine overheating if trimmed up (out) to a point where any cooling water intake holes are above the water line
Trimming the sterndrive down (in) can:
• Help the boat accelerate and plane off quicker
• Generally improve the ride in choppy water
• In most cases, reduce boat speed
• If in excess, lower the bow of some boats to a point at which they begin to plow with their bow in the water while on plane.
This can result in an unexpected turn in either direction called bow steering or over steering if any turn is attempted or if a
significant wave is encountered.
Single‑Engine Trim and Trailer
Single engine applications have a button that can be pressed to trim the sterndrive unit up (out) or down (in).
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90-8M0114081 DECEMBER 2015
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