A stainless steel propeller can last many seasons, but for most boat owners the cost is not insignificant, especially for boats with more than one engine.
With this in mind, Mercury Marine has created a Propeller Demo Program for its dealers that allows a boat owner to test drive stainless steel Mercury propellers. The demo program makes it possible to zero in on the best all-around propeller model and pitch size for your boat before you make that purchase.
Mercury dealers participating in the Propeller Demo Program have on hand a selection of popular stainless steel propeller models in a range of pitch sizes dedicated to demo use. Each dealership devises its own demo program policy, but most request a modest deposit, which may often be applied to the purchase of a new prop. If you decide to make a purchase, the dealer will order you a brand-new prop. The demo props go back on the shelf for the next boater to try.
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.