How to Find the Size of a Boat Propeller
Where to find the information for the size of a boat’s propeller varies by manufacturer, but since propellers aren’t all that big, getting the dimensions is pretty simple.
The best time to note your boat or outboard’s propeller size is when the prop is brand new, since it's easier to read it before it gets installed and worn. Jot down the size and keep it somewhere safe for when it comes time to replace the prop. Here’s a guide to finding the size of a propeller, with examples provided for most of the major prop manufacturers.
How to Find Honda Propeller Size
On a Honda aluminum propeller, the prop size is typically stamped and/or engraved with a set of numbers on the side.
For example, the Honda propeller pictured above has the following set of numbers on the side: 9.25 x 8, which means it has a 9.25-inch diameter with an 8-inch prop pitch. You may see other numbers on another side of a Honda prop, but you’ll know which numbers indicate its size by the Diameter x Pitch formula (9.25x8, 14x19, etc.).
As is the case with the Honda propellers, you may also find other numbers on the prop such as part numbers, like 7-7-8-8-6-3 (also found on the Evinrude-Johnson aluminum prop pictured above). But again, the size number follows the Diameter x Pitch formula (10.3x13, 14x19, etc.).
How to Find Solas Propeller Size
For stainless steel Solas propellers, the prop size information can be found on the outer part of the hub in big bold numbers, making it very easy to read.
Solas incorporated both the prop dimensions and the specific model number all in one sequence. For example, the 143 in the Solas prop pictured above designates the part number. The 13.3-17 portion is what represents the prop size dimensions, with the 13.3 being the diameter and the 17 denoting the pitch.
How to Find Quicksilver/Mercury-Marine Propeller Size
For an aluminum Quicksilver or Mercury Marine propeller, the prop size is stamped or cast into the outer part of the hub. However, it’s a little bit difficult to read.
Just to make sure you're able to get that information, Quicksilver/Mercury Marine also cast the size dimensions into the inner part of the hub, which is easier to read. However, those numbers are going to get covered up by the washer and bolt that holds the hub in place when this prop is installed, so it’s best to take the number down beforehand.
On a stainless steel Mercury Marine propeller, the prop size is much easier to find. The dimensions are laser-etched on the side, but it’s going to wear out very quickly even though it’s a stainless product. For example, on the propeller pictured below, the prop size is clearly visible, 14.6 diameter x 21 pitch.
Because the outer prop dimensions are more prone to fading out, the propeller size can also be found down in the center, stamped onto the hub itself. Once again, it’s best to take the prop size dimensions down before installing the propeller.
How to Find Suzuki Propeller Size
Like Solas, Suzuki also engraves the prop size on the outside of the hub, but without including the part number like Solas does.
For example, in the Suzuki prop pictured above, the 3X represents 3 blades, with 16 being the diameter and 20 the pitch. The R next to the 20 refers to the rotation, in this case standard right-hand rotation.
How to Find Yamaha Propeller Size
For a Yamaha propeller, you’ll find nothing on the outside of the hub, but the prop dimensions can be found all the way on the back side of the inside of the hub.
Basically the only way to find the prop size information for a Yamaha propeller is to actually remove it off of the drive itself, or have it written down before you install the propeller. For example, in the Yamaha prop pictured above, the prop size is 13 ¾ diameter x 19 pitch.
Once again, the best time to find and write down prop size numbers is before installing the prop, since the dimensions could wear or become harder to access post-installation. While it might seem a little old-school to write the dimensions down, sometimes the prop sizes are hard enough to read on a brand new prop, let alone on one that’s been worn out.