How Much Thrust Does a Jet Ski Produce? [Chart]
As a rule of thumb, the average jet ski produces about 1,000 lbs. of thrust. Vintage 2-stroke jet skis typically produced as low as 300-800 lbs., while today’s high-performance models can produce up to 2,000 lbs. of thrust. The amount of thrust a jet ski pump can produce depends on many factors like engine power and the design of the propulsion system.
You’ve come to the right place if you want to drill into this topic. We at JetDrift have compiled all you need to know under one roof!
What is Thrust in a Jet Ski Pump?
Thrust is the force that moves the jet ski in the water. The thrust is generated by the jet ski pump and used both to propel and steer the machine.
Thrust is based on Newton’s Third Law of Motion, which states that for every action in nature, there is an equal and opposite reaction.
Regarding jet skis, the jet pump generates a thrust that accelerates the water backward, and finally squirts out the jet nozzle. At the same time, this fast-moving water jet moves the jet ski forward.
What Factors Does the Performance of a Jet Ski Pump Depends on?
The amount of thrust a jet ski produces varies based on many different factors, including:
- Engine performance
- Engine speed
- Design of the propulsion system
- Condition of the jet ski
There’s no question that the most important factor is engine performance and speed.
The more horsepower the engine has, the more power it can deliver to the pump, translating the rotational motion into axial thrust.
Besides HP ratings, engine speed is no less important. Increasing the engine RPM causes the impeller to spin faster, resulting in more thrust.
The design of the propulsion system also plays an important role. The design and clearance of the impeller, the number of stator vanes, and the shape of the jet nozzle have a significant impact on performance.
What’s more, the condition of these parts can also heavily affect performance. The most common issues with a jet ski propulsion system are as follows:
- Driveshaft misalignment
- Worn or damaged impeller
- Worn or damaged wear ring
- Broken or seized pump bearing
- Clogged intake grate
Any of these malfunctions can significantly reduce the thrust of the pump!
How Does a Jet Ski Produce Thrust?
A jet ski produces thrust by accelerating water through its propulsion system. The jet pump sucks water through the intake and routes it to the impeller. The latter is driven by the engine and intended to accelerate the water. Water is also forced through the jet nozzle, which further increases the velocity and shoots the water out. This squirting water jet produces the thrust that propels the jet ski through the water.
The thrust is also increased by the stator vanes planted inside the pump housing. These metal plates are intended to straighten out the water flow so that more energy can be used for thrust.
Surprisingly, the pressurized water in the jet ski pump is not only used for propelling the machine. Instead, certain models use a small portion of this water for other purposes.
For example, most jet skis are still manufactured with open-loop cooling systems. These industry-standard cooling systems use the external water coming from the jet pump to cool down the engine.
Besides engine cooling, this water is also often used for cooling the exhaust and the intercooler on supercharged models.
On top of that, Yamaha WaveRunner’s visibility spout is fed by the pump as well.
How Much Thrust Does a Jet Ski Produce?
A jet ski pumps’ performance varies depending on the make and model. The general rule is that a stock jet ski can produce about 300 – 2,000 lbs. of thrust.
Vintage 2-stroke jet skis are powered by low-performance twin engines and basic (often plastic) jet pumps. These models could only produce 300-800 lbs. of thrust.
In contrast, modern 4-stroke jet skis can put out no less than 800-2,000 lbs. of thrust.
For your convenience, we’ve compiled some of the available specifications into one chart:
Jet Ski Thrust Chart
|Model||Amount of Thrust (lbs-ft)|
|1986 Yamaha WaveRunner 500||309|
|1988 Sea-Doo SP||367|
|1989 Kawasaki Jet Mate||507|
|1990 Yamaha WaveRunner III 650||385|
|1990 Sea-Doo GT||504|
|1994 Yamaha FX-1||496|
|2009 SX-R 800||750|
|2021 Kawasaki Ultra LX||957|
|2022 Kawasaki STX-160||957|
|2022 Kawasaki SX-R 1500||957|
|2022 Kawasaki Ultra 310 LX||1890|
How Much Water Can a Jet Ski Pump?
Thanks to its incredible performance, an average jet ski pump can produce a flow rate of around 1,000 gallons per minute. High-performance supercharged jet skis can even exceed this range!
You need this information, especially when you want to use a Flyboard or another hydroflight device.
These units are powered by regular jet skis and require at least 1,000 GPM to keep their rider in the air.
Hydroflights come with a hose that has to be directly attached to the jet ski’s propulsion system.
Takeaways – How Much GPM does a Jet Ski Produce?
The average jet ski produces about 1,000 lbs. of thrust, translating to a water flow of approximately 1,000 GPM. The exact numbers vary from one model to the next, but these can be good starting points if you are looking for some hard numbers.
As you might assume, the early jet skis with underpowered 2-stroke engines were much less powerful than their modern counterparts. These crafts could only generate about 300-800 lbs. of thrust.
In contrast, the latest 4-stroke models can easily put out about 800-2,000 lbs. of thrust.
For example, non-supercharged Kawasaki jet skis utilize the same pump, rated at 957 lbs., while the flagship supercharged models come with a far more powerful pump, rated at 1,890 lbs.
Finding the same specifications for the latest Sea-Doo and Yamaha jet skis is hard to impossible, but the performance of these machines is more than likely in the same ballpark.
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