Any practical boat owner knows to change the engine oil, swap out the impeller every year or two, and change worn belts before they break. But the propeller is much more likely to be overlooked. Choosing the wrong prop or continuing to use a damaged prop can decrease boat performance, increase fuel consumption, and potentially damage your engine and transmission. Here are five conditions that warrant a closer look at your prop.
With the prop out of the water, tap each blade in turn with block of wood. A different tone may indicate a serious problem.
If your prop has too much pitch (see "A Few Important Definitions" below) like the one above, the engine will have a lousy "hole-shot" — the ability to jump up on plane quickly — and will lug (or drag). It's like starting from a stoplight with your car in third gear — not only will it take much longer to accelerate, the engine has to work hard at low speeds, which places a tremendous load on the pistons, crankshaft, and bearings. This, in turn, can cause detonation, piston seizure, and other engine damage.
Boat dealers and service experts will tell you that incorrect prop selection is a leading cause of poor engine and boat performance.
Mercury Marine, the world’s largest supplier of propellers for recreational and commercial boats and engines, provides a wide array of propeller options to ensure there is a propeller for every boat application.
The Mercury Propeller Selector tool on www.MercuryMarine.com helps boaters select the best propeller model and pitch for their boat. The Prop Selector is essentially a digital catalog that aids in selecting the most appropriate propeller.
To find your propeller on www.MercuryMarine.com, click on Propellers, then click on Mercury Prop Selector. Once there, follow the simple steps to select your boat type, boat usage and engine information, and the Selector will provide a recommended prop family. The Selector then helps you determine the correct pitch of your propeller.