If you want to buy a suitable and cost-effective 40HP Outboard Motor 2 Stroke for your beloved boat, you must learn to measure the shaft length of the outboard motor. When choosing to purchase a new outboard motor, brand, horsepower, and shaft length are all key parameters. If the shaft length is not appropriate, it is just like wearing a pair of shoes that do not fit your feet. It is not only uncomfortable but also makes walking difficult. Today, we will introduce you to the outboard boat motor and the shaft length of the outboard motor.
What Is The Shaft Length Of An Outboard Motor? Is It Important?
The shaft is similar to a vertical pole, and the shaft length is the length of this vertical pole. Let's think about it this way: when we install the outboard boat motor engine at the stern of the boat, a vertical pole extends into the water, with a propeller hanging at the end. This shaft needs to be long enough for the propeller to submerge into the water and reach the appropriate depth.
The correct length of the shaft is crucial and serves as the foundation for efficient power transmission. If the shaft is too short, the propeller will spin idly, fail to receive sufficient force, and is prone to sucking in air, making steering difficult. Conversely, if the shaft is too long, it not only risks hitting underwater obstacles, making forward movement challenging, but also causes the vessel to lose balance and increases resistance.
How Can The Length Of An Outboard Motor Shaft Be Measured Correctly?
First, prepare the measuring tools. A tape measure is enough. Of course, our beloved boat is indispensable.
The measurement steps are as follows:
① First, measure the boat (determine the measurement reference plane & measure the height of the stern board):
We need to level the boat and find the stern board (the vertical board at the rear of the boat is called the stern board). Measure vertically from the top edge of this board all the way down to the lowest point of the boat's bottom. After measuring, we need to know:
• Short shaft: approximately 38 centimeters.
• Long shaft: approximately 51 centimeters.
• Extra-long shaft: approximately 64 centimeters.
② Understanding the definition of shaft length:
The shaft length of a 40hp outboard motor 2 stroke is not what we might imagine, which is measured from the top of the head to the bottom of the feet. The correct way to measure it is: starting from the bottom of the engine (the side close to the stern), measure down to the lower edge of the anti-vortex plate. The anti-vortex plate is a horizontal plate above the propeller. When the boat is in motion, the anti-vortex plate is submerged under the water surface.
③ How to match them correctly?
The golden rule is that the shaft length of the outboard boat engine should be greater than or equal to the height of the transom of the boat. For example, if you measure the height of your boat's transom to be 51 centimeters, then choose an outboard motor boat engine with a shaft length of 51 centimeters or slightly longer (around 53 centimeters). Never choose a shorter one! Just like you wouldn't buy 1.7-meter trousers for a person who is 1.8 meters tall.
And for special cases, special treatment should be given.
• If you enjoy speedboat racing or frequently navigate rough waters, it is recommended to choose the extended version.
• If you have an inflatable boat or a rubber dinghy, be sure to follow the manufacturer's recommendations.
• If your boat is equipped with a raised support, you must select an engine with a longer shaft.
To see if it fits or not, just install it and check for yourself.
• Ideal state: The small wing is just hidden under the water surface (about the depth of a fingernail);
• If you see water splashing from the wing: It indicates that it is too short;
• If the wing is completely invisible: It might be too long.
Also, don't be misled. It's not just about having a powerful engine. If the shaft length is incorrect, even a powerful engine will be of no use and will consume more fuel instead. It's also not about looking approximately the same depth in water. Static measurement is just the basis.
A good boat needs a good outboard motor, and the key lies in the shaft length. Measure the dimensions accurately, and your boat will run smoothly, save fuel and be safe. The right match is the beginning of a perfect dialogue between power and the vessel. For more information about 40HP Outboard Motor 2 Stroke, please contact us:
• +8615094051894
• inquiry@klsautoparts.com
• Room 1705, Yihe Blue Diamond, No. 154, West Section of Second Ring South Road, Yanta District, Xi'an City