What are the Parts of a Jet Ski? [Video]
It’s safe to say that the main parts of a jet ski are as follows:
- Body (hull and top deck)
- Engine with fuel line and cooling system
- Handlebar and controls
These major groups can be broken down into further smaller units.
If you want to find out more about the parts of a jet ski, you are in the right place.
We at JetDrift have compiled all of them into this post!
Body of the Jet Ski
The largest and most noticeable part of a jet ski is its external body. This huge shell consists of two parts, which are known as the hull and the top deck. This watertight body houses the engine, fuel line, electronics, and storage bins. Also, you can find many other smaller parts attached to the outside of this body like the seat, handlebar, cleats, and the reboarding step.
Let’s drill into the details and take a closer look at each!
Simply put, the hull is the lower part of a jet ski’s body. This shell floats in the water and keeps the machine afloat. Jet skis feature a “V-shaped planing” hull that you can also find on many powerboats. They are typically made of regular fiberglass, SMC, or Polytec.
If you want to dive deeper into this topic, you can compare different jet ski hull designs and materials here.
What is the Top Deck on a Jet Ski?
The top deck of a jet ski is the shell that covers the top of the hull. Therefore, contrary to popular belief the top deck is not considered to be part of the hull. Instead, these large shells are two completely different units, which are like two halves of a walnut. The hull is actually the bottom of the jet ski which runs in the water, while the top deck works like a roof above it.
Thanks to their watertight sealing, water can’t leak into a jet ski’s body. (Instead, it’s much more common for a jet ski to leak near the carbon seal.)
The top deck is always part of the design, as it’s the largest and most conspicuous part of the machine.
The top decks of Sea-Doos feature a more futuristic design, while Yamaha and Kawasaki jet skis are a little more traditional.
The major parts of a jet ski top deck are as follows:
Just like on boats, the rear platform of a jet ski is often called the swim platform. It comes in handy when you reboard from the water, but you can also store some gear on it. What’s more, you can even fish off off this platform!
The footwells on a jet ski are two ditches on both sides of the deck. They are designed to accommodate your and your passenger’s feet during the ride. Footwells can keep water away at a certain level, but if you ride hard or the water is choppy you can expect some water to get inside them. That’s why the newest jet skis come with footwell draining systems.
The footwells and the swim platform are typically covered with mats, which provide better traction.
Most jet ski decks feature a hood on their front. But instead of the engine you can find a storage bin under this hood.
To feed the engine with fresh air, the top deck always features some vents.
The top deck of a jet ski typically houses one or more storage bins depending on the model. The majority of jet skis come with two or three separat storage bins, which are as follows:
The biggest storage bin is always located on the front of the jet ski, under the hood. Unfortunately, this bin on most jet skis is not completely waterproof and hard to access on the water.
This is why this storage area on flagship Sea-Doos can be accessed from the seat. You can basically pop up the entire handlebar to access the storage area under it. It’s a great feature if you spend the whole day on the water!
Compared to the front storage, the glovebox on a jet ski is a much smaller unit. If you sit on the saddle, you can find this glovebox directly in front of you. The glovebox can accommodate your phone, sunglasses, or other small types of gear. Some of the newest jet skis have an enclosed waterproof box inside their glovebox, but the majority of jet ski gloveboxes are still not completely dry.
Some jet skis have a smaller rear storage unit, which is located under the seat. It can be extended with an OEM “stern-mounted storage,” which is actually a bag strapped behind the seat.
Many other smaller parts that are mounted to the hull or the top deck, but the most important of these are the following:
- Bow eyes (for docking, anchoring, or even towing your jet ski)
- Ski eyes (for watersports)
- Cleats (for docking)
- Reboarding step (for reboarding after swimming)
- Rear grab handlebar
- Flushing ports
- Drain plugs
- Gas tank cap
- LinQ connectors (exclusively on Sea-Doos)
- VIN number
Besides these basic parts, you can customize your jet ski with endless OEM and aftermarket additions.
The most common are probably wakeboard racks, rear racks with coolers (and other jet ski fishing gear), storage bags, and extra fuel cans.
Jet Ski Seat
Another major part of a jet ski is its seat, which is known as a saddle as well.
The seat of jet skis usually consists of one or two parts depending on the model. They are well padded and fit into the design of the body.
The seats are covered with skin-friendly materials, which are typically quite durable. However, after some years the seat of many jet skis needs to be reupholstered.
The seats of “sit-down” jet skis can typically accommodate two or three riders, but it’s good to know that stand-up jet skis are still available on the market.
As the name suggests, you can ride these machines in a standing position.
Engine and Fuel Line
As a rule of thumb, most modern jet skis come exclusively with 4-stroke engines. These power sources feature 3 or 4 cylinders and provide no less than 60-310 HP.
The performance of the flagship jet ski engines is boosted with a supercharger and crank out an amazing 250-310 HP.
This outstanding performance makes jet skis the most powerful powersport vehicle available!
In the past, every jet ski was powered with a 2-stroke engine, but after 2006 4-stroke technology has become more prevalent due to environmental considerations.
Therefore, if you’re looking for a 2-stroke jet ski your only chance is to purchase a vintage machine.
If you want to compare different power sources heat-to-head, don’t miss our detailed post about jet ski engines!
Fuel Line and Air Filter
Just like any other gas-powered machine, jet skis also feature a complete fuel line.
Since jet skis are known for their thirsty engines, they typically feature a large fuel tank. The fuel line also includes a fuel filter, fuel pump, injectors, and hoses.
The majority of vintage 2-stroke jet skis were manufactured with carburetors, however, a few of the latest models were already fuel-injected.
In contrast, today’s jet skis are designed exclusively with injectors. No more “carb work” before rides!
To clean the incoming air, jet skis also have air filters.
To keep their engines cool, jet skis feature a cooling system.
The first jet ski engines were air-cooled, which were prone to overheating. Let’s face it, the engine on a jet ski sits in an enclosed shell, which completely blocks incoming air.
That’s why the new models use the external water to cool their engines.
Sea-Doo uses a closed-loop cooling system while other manufacturers stick with open-loop cooling. The latter is still considered to be the standard in the marine industry.
In an open-loop cooling system external water enters the engine and circulates around the cylinders and the exhaust to keep them cool.
In contrast, Sea-Doo’s closed-loop cooling works like the cooling system of a car. It features a radiator which is bolted to the bottom of the craft.
A coolant liquid transfers the heat from the engine to the radiator, which is submerged into the external water to keep it cool. This system is completely closed, which is why it’s called “closed-loop” cooling.
However, it’s good to know that the intercooler and the exhaust are cooled with external water even on Sea-Doos. Because of this, Sea-Doos have to be winterized as well!
The jet pump is a key part of a jet ski as it’s designed to propel the jet ski on the water.
The pump on a jet ski is mounted onto the outside of the hull and features many different parts. Let’s get down to the nitty-gritty and talk about them in detail!
Pump housing: A larger metal housing that accommodates the impeller, wear ring and ends in the jet nozzle.
Impeller: The impeller on a jet ski does the same job as the propeller on boats. It speeds up the water, which squirts out of the rear side of the pump (through the nozzle). Finally, this water jet propels and steers the jet ski!
Wear ring: On Sea-Doos the impeller is surrounded by a plastic ring known as a wear ring. It can be easily replaced in case of damage. Other types of jet skis lack this ring meaning that their impeller is directly surrounded by the pump housing.
Jet nozzle: The jet nozzle is a cone-shaped metal pipe attached to the rear side of the pump. The role of this part is to direct the water jet coming from the pump. When you turn the handlebar, you actually move this jet nozzle left and right, which finally steers the machine.
Reverse bracket: The reverse bracket on a jet ski is a foldable bracket behind the jet nozzle. The main idea behind this bracket is that it can reverse the direction of the water jet. This reversed water flow causes the jet ski to slow down or move in reverse.
Driveshaft: The impeller and the engine are connected by a durable metal shaft, which is referred to as the driveshaft.
Carbon ring seal/coupler: Since the pump and the impeller are located outside of the body, the driveshaft has to break through the hull at a given point. It simply means there’s a hole on the hull below the waterline through which the driveshaft passes. To prevent external water from leaking into the hull this hole is always carefully sealed. For this purpose, Sea-Doos use a carbon ring, while Yamaha and Kawasaki jet skis feature a coupler.
Intake grate: The intake grate on a jet ski is a metal grate bolted onto the pump’s intake. It’s designed to keep debris, ropes, seaweed, and trash away from the pump, which is always a hassle to remove if they get stuck!
Jet Ski Controls
Let’s move on and see the most important controls of a jet ski!
Handlebars: Just like any other powersport vehicle, jet skis are also handlebar steered. On the end of the handlebar you can find two comfortable grips. As mentioned, turning the handlebar causes the jet nozzle to turn which finally steers the jet ski. Just like on a motorcycle or a bike, you have to turn the handlebar in the same direction you want to go.
Control Levers: Unlike motorcycles, which are exclusively manufactured with twist throttles, jet skis have throttle levers. This smaller lever is placed in front of the right grip and looks like a brake lever on a bicycle. You can control the throttle with the right lever, while the brake and reverse lever is located on the left.
Buttons: Besides these two levers, you can find many different buttons on the handlebar, especially on newer jet skis. With these buttons, you can start/stop the engine, control the trim, cruise mode, sound system, or many other functions. The layout and the function of these buttons may vary from one model to the next, but are always clearly stated in the operator’s manual.
Shut-off switch: One of the most important parts of every jet ski is arguably the shut-off switch. This is actually a safety feature that stops the engine if you accidentally fall into the water. The switch has to be connected to your wrist or life jacket with a flexible chord.
Today’s jet skis are stuffed with a lot of electronics, which can cause many malfunctions. The most important electric components of jet skis are as follows:
Dashboard/gauges: Vintage jet skis typically featured some basic analog gauges. In contrast, many of the newest models come with a large dashboard, which is actually an LCD screen on the flagship crafts. It shows your speed, engine RPM, fuel level, and lots of other useful info about your cruise.
Sensors: Although they are invisible, there are many sensors in the different systems to monitor the temperature, exhaust gases, and the fuel usage. A malfunction in these systems causes a fault code or a flashing control lamp on the dashboard.
Computer: As you can see, jet skis come with many different electronic parts. Unlike vintage models, on modern jet skis the ignition, injectors, throttle lever, trim, reverse bracket, and many other parts are electronically controlled. To control and synchronize these systems, jet skis have a tiny built-in “computer,” which is often called an ECM or ECU (electronic control unit).
Wiring: To link the different systems jet skis feature a large amount of wiring. Over time, the connectors of these wires tend to loosen or corrode, which can cause a lot of headaches for owners. Cable corrosion is a typical issue especially on jet skis that are used in saltwater.
Sound system: Some high-end jet skis come with a built-in or even portable sound system, which can be connected to your phone with Bluetooth.
Battery: Every jet ski has a battery that is charged by the stator.
Bilge pump: Keeping safety in mind, a bilge pump is becoming standard on more and more jet skis. It’s a small pump installed on the lowest part of the hull. It removes bilge water automatically or at the touch of a button depending on its design.
What is the bottom of a jet ski called?
The bottom of a jet ski is called the hull. There’s a “spine” on the bottom of a jet ski’s hull that is known as the keel, while the flatter area towards the rear is called the pad.
What is the right side of a jet ski called?
The right side of a jet ski is known as starboard.
What is the left side of a jet ski called?
The left side of a jet ski is called the port.
What is the front of a jet ski called?
The front of a jet ski is often referred to as the bow.
What is the rear of a jet ski called?
The rear side of a jet ski is the stern.
Conclusion – What are the Parts of a Jet Ski?
It’s safe to say that the main parts of a jet ski include: the body, seat, engine, pump, and controls.
The hull consists of two larges shells, the hull is the bottom of the machine, which sits in the water. The hull is covered by the top deck thereby creating a watertight body.
To keep it dry and safe, the engine is located inside of this enclosed space, while the pump is mounted on the bottom of the hull.
The main parts of the pump are the housing, impeller, and the jet nozzle. The engine and the pump are connected by the driveshaft.
Besides these major parts, there are many smaller parts of a jet ski, which all have their own function.
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