Suzuki outboard propeller — correct pitch angle and diameter for power
In the Suzuki propellers product group, you will find a comprehensive range of original Suzuki aluminum propellers for different engine powers, from 2.5 horsepower to 140 horsepower (e.g. 7-3/8 x 5-3/8" for the 2.5 hp engine under 2012 model, 7-1/2 x 6-1/2" and 7-1/2 x 7" for small 4–6 hp engines, 9-1/4 x 7" for 8–20 hp engines and 13 x 19" for DT100/115/140 series engines). The propeller size is always indicated in the diameter x pitch angle format in inches, and the right choice depends on both the engine power and the type and purpose of the boat — too high a pitch angle strains the engine and slows down acceleration, while too low a pitch angle prevents top speed from being reached.
Aluminum is the most common and affordable propeller material for lower-power engines and is durable enough for most regular boating, although it is more susceptible to denting when bottoming out than a stainless steel propeller. When replacing a propeller, it is also worth remembering the mounting hardware: the range includes propeller nuts and shear pins suitable for Suzuki (e.g. DF2.5–DF6 and DF4A/5A/6A, DF25A–350A models and DF8A/9.9A, DF15A/20A models), which should always be replaced with new ones when replacing the propeller — the used pin is designed to break once to protect the gearbox in the event of a collision, so the old pin should never be reused.
It is worth checking the condition of the propeller regularly: dents, nicks or uneven wear on the edges of the blades cause vibrations, reduce efficiency and, in the worst case, can strain the engine crankshaft and bearings. If the engine vibrates unusually or fuel consumption has increased for no apparent reason, the cause is often a damaged or incorrectly sized propeller — a significantly lower top speed than usual at the same RPM is also a typical sign of propeller damage.
Before ordering, it is a good idea to check the engine nameplate or instruction manual for the exact model and year, as Suzuki's propeller range has changed over the years and the same power class may have used a different mounting shaft in different generations of engines. Keeping a spare propeller on the boat is recommended, especially on longer trips — propeller damage during the trip can otherwise ruin the entire trip without a spare part.
Although the selection focuses on aluminum propellers, it is worth remembering that the condition of the propeller shaft and gearbox also affects the final result — even a new propeller will not fix vibrations caused by a worn shaft bearing or a bent shaft. If the vibrations continue even after replacing the propeller, the cause is likely to be found elsewhere in the drivetrain.