TUNING
WARNING! Always perform any tuning trials on protected and uncongested waters. More extreme tuning trials should be performed with appropriate safety gear and a support boat. Never exceed your driving skill levels.
Engine Height and Trim
The transoms on our boats are molded with a height to accomidate most all outboards with the intended shaft length. Depending on your engine and prop this may be far less than optimal. Raising the outboard up reduces gearcase wetted surface area. Even 1/4" can affect holeshot and top speed.
Load the boat as you would normally run it.
Loosen your outboard mount screws. Lift the engine enough to slide a shim between the transom top edge and engine mount. Start with a small shim such as 1/4" plywood. Run the boat. If the prop ventilates in a corner and you lose significant speed the prop is too high and you need to lower the motor back one step. Continue raising the engine in increments until performance degrades or the prop starts ventilating.
Engine trim can also dramatically affect performance. Start with the gearcase's ventilation plate level with the bottom of the boat. When running the boat should plane easily but may have a slightly bow down attitude. Trim the engine out one notch. Typically just move the trim/tilt pin out one hole set. Run the boat again. The boat should still plane in reasonable time. It should also feel light and responsive at full speed but yet not twitchy or uncontrolled. If the boat is still stable trim out one more notch. If the boat feels uncontrolled at any speed don't increase to WOT, stop and reduce the trim setting. Also watch the prop wash. If it is being thrown up and scattering into a wide spray pattern you may be trimmed too high. If it's tight and narrow you may be trimmed too low.
If you find the optimum trim setting to be between two notches on your engine simply shim out a tad. You can loosen the engine mount screws and slide a thin shim between the back of the transom and the upper edge of the outboard mount. This will effectively trim the engine a partial notch.
