How to Trim Your Outboard for Optimal Performance

Improve speed, ride and fuel economy with basic adjustments.

Adjusting an outboard’s trim in or out is one of the most effective ways to improve a boat's overall performance. Trimming the outboard adjusts the boat’s attitude, or the angle of its bow into the water, which can help dial in the best ride by compensating for vessel load and sea conditions. In most cases, properly trimming also enhances fuel economy and top-end speed

Experimenting with engine trim should be practiced in small steps until you acquire a solid, working feel for how your boat reacts to changes. From there, fine-tuning the ride through engine trim, throttle and trim tabs becomes second nature

Here are some of the basics.

Trim for Results

When a boat is at idle, trim the outboard completely in, or down. This positions more of the lower unit into the water at a nearly vertical attitude, which provides unobstructed water flow to the prop. From this position, when you throttle up, the prop immediately "bites" and propels the boat onto plane. Threats of cavitation or "blowout" (where air and impeded water flow cause a prop to lose all bite and spin ineffectively) are virtually eliminated.

Going Up

Once a boat is on plane and operating at a consistent speed, trim out to raise the outboard a bit. Doing so raises the bow and leaves less of the lower unit in the water, which reduces drag. Cruising speed picks up, and fuel economy improves as a result.

Based on the boat's attitude and ride, trimming out more can further improve performance. At wide-open throttle, trimming should yield higher rpm and top-end speeds. However, trimming out too far can degrade performance and cause the boat to porpoise, or bounce.

Going Down

Trimming in lowers the outboard and allows more of the hull to settle into the water, particularly at the bow. This is advantageous when running directly into choppy water because it better positions the hull to slice through the water and allow a smoother ride. Again, dialing in the most comfortable ride comes down to acquiring a feel for your boat and how it reacts to engine trimming.

Those Turns

When entering a turn, trim the outboard in for maximum prop bite and handling, as well as superior planing capability when throttling out of the turn. Once you start to straighten out, begin trimming out the outboard and dialing in your most efficient cruising speed.