Mercury MerCruiser Owner's Manual page 31

For best performance trim the sterndrive unit so that the boat bottom is at a 3‑5° angle to
the water.
Trimming the sterndrive unit 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 unit down(in) can:
• Causes the boat to accelerate and plane off quicker
• Generally improve the ride in choppy water
• In most cases, reduce boat speed
• In excess, can cause bow steering (unexpected turning) by lowering the bow of the
boat so that it plows the waterline while on plane.
90-899883295 JUNE 2008
Section 2 - Getting to Know Your Power Package
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