Boating Without Adaptive Speed Control
To get a boat up on plane without Adaptive Speed Control, push the throttle full forward, pulling back once on plane. Trim the engine to lift the hull, reduce drag, and increase engine rpm even with constant throttle. Heavy boats require more throttle to reach the same rpm as a lightly loaded boat.
Prop selection for this scenario is relatively straightforward. Too little pitch will result in engine revving past its recommended rpm operating range. Too much pitch will limit the engine from reaching its peak rpm for maximum speed.
250R & 300R FourStrokes
With Mercury Racing’s new V-8 FourStroke outboards, Adaptive Speed Control constantly adjusts the engine throttle and available airflow to achieve or maintain a given rpm. When the boat’s load curve is within expected limits, getting on plane no longer requires a throttle overshoot or pull-back to maintain speed.
Adjusting trim will still lift the hull and allow higher efficiency, however, engine rpm will be maintained unless helm throttle demand is increased or already at 100%.
Propping for Maximum Performance
The largest difference when propping for Adaptive Speed Control is experienced when running the engine at the top of the recommended operating rpm. For example, running a 300R with an under-pitched propeller, on a lighter than normal boat load, or over-trimmed will result with the engine reaching its maximum 6400 rpm operating range without using maximum power. In the past, the engine would continue to climb in rpm until the rev limit was reached.
With Adaptive Speed Control, the 300R Engine Control Unit (ECU) will automatically pull power to maintain the 6400 rpm limit without any indication to the driver. The only way to verify 100% power output at 6400 rpm is to have your dealer run an engine diagnostics test via the Mercury G3 tool. Any rpm less than 6400 (or max rated rpm) with the helm throttle control at full forward or 100% will result with full power output of the engine.