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March 27, 2014

Outboard Basics: Keep Your Engine Running Strong

Fish longer with proper engine knowledge and care


An outboard directs its thrust. This is also a big advantage when it comes to steering because directed thrust offers superb control when turning, particularly at low speeds. Outboards are not unique in this respect: Sterndrives and pod drives offer directed thrust, but the engine resides inside the boat.

The vast majority of saltwater boats today use one of two types of steering: hydraulic or power-assisted hydraulic. For single- and most twin-outboard applications, hydraulic steering ranks as the most popular. In these systems, from companies such as SeaStar Solutions and Uflex, the helm is a manual pump. As you turn the wheel, it delivers hydraulic pressure to an actuator attached to the outboard. Check valves in the system eliminate any feedback, easing the task of steering.

Power-assisted hydraulic steering is based on the same principle but uses an electric motor to help drive hydraulic pressure. This is helpful with steering multiple high-horsepower outboards. Mercury, SeaStar and Yamaha offer such systems. Joystick low-speed steering, which uses power-assisted hydraulic actuators, is also available for multiple outboard -installations from the same companies.

While all types of hydraulic-steering systems have proved reliable, you should -periodically check the fluid level and “bleed” the lines if steering becomes sloppy due to air in the system. Also, regularly look for hydraulic fluid leaks at the helm, hose connectors and around the actuators. If you see any leaks, have the system serviced as soon as possible.

Shaft Length

Outboards come in four shaft lengths: S (15 inches), L (20 inches), XL (25 inches) and XXL (30 inches). Shaft length is driven by transom height, and except for some technical-poling skiffs, most saltwater-fishing boats run XL or XXL outboard shafts. The idea is to position the lower unit below the running surface to supply the propeller with enough clean water to achieve a “bite” and efficiently propel the boat. An offshore-fishing boat with triple or quadruple outboards usually has both, with the longer shafts for the center engine(s) and shorter shafts for the outside engines. This is because the V-shape of the running surface at the transom creates a deeper hull toward the center than on either side.