I just got my new 15 HP Yamaha 2 Stroke Outboard Motor, but I'm not sure how to install it correctly. Installing an outboard motor is just as scary for first-time buyers as picking the correct one. The height of the installation is especially important; even a small difference in height can make a big effect. If you don't install the outboard boat motor correctly, it won't work as well as it could and could even cause difficulties like idling and overheating. How can I figure out the right height to put the outboard engine?
How High Should The Outboard Motor Be Installed?
The installation height of the marine outboard motor is the distance between the motor and the stern plate and the waterline. The main rule for proper installation is that the anti-ventilation plate should be about level with the extended line of the keel at the bottom of the boat, or 1–2 centimetres higher. Some people might wonder, "What is an anti-ventilation plate?" The anti-ventilation plate is the metal plate that goes across the top of the propeller. It's an important part that keeps air from getting into the propeller and makes sure it works well.
What Makes The Height Of The Outboard Motor Installation So Important?
People who don't know how it works might think that a small variance in height doesn't matter as long as it's installed. In real life, the consequences will be very different. If you install something too high, it can cause big problems:
• If the marine motor is too low, the boat will go slower, use more gas, and put more strain on the engine. In addition, the big splash will make it hard for the boat owner to see and make decisions. This is like riding a bike that is stuck in mud-slow and hard.
• If the marine engine is positioned too high, the propeller will spin freely, which will make the thrust unstable. It will also lose its grip on water when you turn, and if it doesn't get enough coolant, the engine can overheat.
How Can You Find Out What The Normal Installation Height Is?
1. Line up the hull: Put the boat on its side and find the keel line that runs from the bottom of the hull. Look at where the anti-ventilation plate is. The anti-ventilation plate should be at the same height as or a little higher than the keel line (1–2 cm). This is the safest height.
2. Match the height of the sternplate: Outboard motors come in short-shaft, long-shaft, and extra-long-shaft models, and each one fits a different height sternplate. A 38cm sternplate height works with short-shaft outboard motors, a 51cm sternplate height works with long-shaft outboard motors, and a 63cm sternplate height works with extra-long-shaft outboard motors. This means that the height of the sternplate and the length of the outboard motor's shaft are the same.
3. Real Water Testing: After putting the outboard boat engine on, test it in the water. Make sure it slides easily, grabs the water nicely when you turn, has perceptible freewheeling, and is stable at high speeds. If any of these problems happen, move it up or down by 1.5 cm at a time.
Different Kinds Of Boats Need Different Heights For Installation
1. If you have an inflatable or rubber boat, you need to put it a little lower, which means that the anti-ventilation plate should be a little below the bottom of the boat. The bottom of inflatable or rubber boats is incredibly flexible, which makes it easy for air to get through.
2. For boats made of aluminium alloy or fibreglass, standard installation is fine. This means that the anti-ventilation plate should be level with or slightly higher than the bottom of the boat. Boats made of aluminium alloy or fibreglass have stiff hulls that let water flow more smoothly.
3. For boats that go fast or have been changed, the installation height needs to be a little higher, so the anti-ventilation plate should be a little higher than the hull. This cuts down on drag and speeds things up.
Here are some instances of how not to install something:
1. Lower is safer. Not right. If you put the boat outboard motor too low, it will have a big effect on speed and fuel use.
2. The higher, the faster. Not right. If the outboard engine is too high, over a certain point, it will only cause slippage, which will slow down the boat.
3. All boats should be installed at the same height. Not correct. varied boats have varied hull shapes and heights that they need to be.
4. Putting it in without testing. Not true. Theory and practice are not the same thing; a sea trial is necessary. Boat owners who have been around for a while have their own simple and useful advice: "Align with the hull, don't bury the snorkel, and find out the height through a sea trial."
Conclusion
The height of the outboard motor installation is not a set number; it changes depending on the vertical dimension. You need to guess how much it will cost based on the type of boat, the length of the shaft, and how you plan to use it. You should also realize that the right installation height not only makes the boat go quicker and use less gas, but it also makes the outboard motors last longer.
Still not sure which outboard motor fits your boat? Contact KLS Supplier today for expert advice and factory-direct pricing:
• +8615094051894
• Room 1705, Yihe Blue Diamond, No. 154, West Section of Second Ring South Road, Yanta District, Xi'an City
FAQ
Q1: How can I immediately tell whether my outboard motors are too high?
A1: If the car noticeably idles as you speed up or turn, the wheels are too high.
Q2: Will putting outboard motors too low hurt the engine?
A2: No, not right away, but over time, it will raise the load and fuel demand, and it could cause the engine to overheat or work less well.
Q3: Can I fix problems with the height of the installation by changing the propeller?
A3: It can make things a little better, but it can't take the place of the right installation height. If you have height problems, the first thing you should do is move the engine.
Q4: Does the installation height need to be changed for a new boat?
A4: Maybe. The best height will depend on the load and the water conditions. After sea testing, it is best to make small changes.
Q5: Can I change the height of the outboard motor by myself?
A5: You can change it yourself if it has adjustable mounting holes and is a standard mounting plate.
References
Wikipedia Outboard Motor