MerCruiser 8.1 MAG, Owner'S Manual

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Section 2 - Getting to Know Your Power Package
90-864839070 AUGUST 2007 Page 31
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 unit for trailering, beaching, launching, low
speed (below 1200 RPM engine speed) and shallow water operation.
!
WARNING
Excessive trim can cause serious injury or death at high speeds. Use caution when
trimming the sterndrive, and never trim out beyond the gimbal ring support flanges while
the boat is underway or at engine speeds above 1200 RPM.
For best performance trim the sterndrive unit so that the boat bottom is at a 3‑5° angle to
the water.
3 - 5
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Trimming sterndrive unit up/out can:
• Generally increase top speed
• Increase clearance over submerged objects or a shallow bottom
• Cause 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
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Trimming sterndrive unit down/in can:
• Help the boat accelerate and plane off quicker
• Generally improve the ride in choppy water
• In most cases, reduce boat speed