How Do Outboard Motor Shifter & Throttle Controls Work

by Steve Smith

Throttle Overview

An outboard motor shifter and throttle control is the unit that controls the amount of throttle or speed of the outboard motor. The throttle control is a lever that can be pressed forward to increase the speed of the boat. When the throttle level is pushed forward, it opens the engine throttle in the outboard, which means that more air and fuel is being allowed into the combustion chamber at a higher rate of frequency. This causes the engine to run faster, which in turn delivers more spin to the propellers. A typical throttle control and shifter has one lever for each outboard installed. The levers can be moved independently, so when one is pushed forward or "throttled up," the other outboards do not "throttle up."

Shifter and Gears

On each throttle control there is a gear shift as well as a throttle. Each is controlled by the same lever. The lever operates the transmission along with throttle. When the lever for one outboard is set to the center position, the boat is out of gear. Push the lever forward and the boat goes into gear. It engages the transmission, which relays the drive power from the engine outboard to the propellers. The transmission will also shift from forward to reverse, changing the direction of spin or the propellers. When you move the lever backwards, it switches the drive mechanism to spin the propellers backwards instead of forwards. This is how a boat is moved in reverse.

Motor Shifter or Trim

On the control panel which contains the throttle and gear levers are buttons that control the position of the outboard motors--this is called trim. The outboards can be tilted up out of the water by hydraulics when you press the trim buttons. These buttons power the hydraulics which raise and tilt the engines back and up out of the water.

About the Author

Steve Smith has published articles on a wide range of topics including cars, travel, lifestyle, business, golf, weddings and careers. His articles, features and news stories have appeared in newspapers, consumer magazines and on various websites. Smith holds a Bachelor of Arts in English and journalism from University of New Hampshire Durham.