Are All Jet Skis 2-Stroke?

If you are looking at used jet skis, you may have come across a lot of 2-stroke jet ski models. As a prospective buyer of a personal watercraft, you may be wondering if jet skis only come with 2-stroke engines or if there are other options out there?

Jet skis are not all 2-stroke. There are two types of engine options for a jet ski: a 2-stroke engine and a 4-stroke engine. The 4-stroke engine has become essentially universal in recent years.

In fact, Sea Doo, one of the leading manufacturers of jet skis, phased out the 2-stroke engine in 2007. Yamaha and Kawasaki both sell just 4-stroke skis, as well. My kids and I fell in love with the freedom and fun that jet skis allow after renting them a couple of times. If you are like us, you may find yourself in the market for one and start doing some research.

While you’ll want to consider the style, shape, and color of your future jet ski, if you are going to put out the money to buy one of these expensive water toys, you want all the facts, right? And the truth is that the engine size is an important determiner of your experience on a jet ski. 

What is A Combustion Engine?

Before we get into the nitty gritty of different kinds of engines, let’s talk about what the general makeup and function of an engine are. A gasoline powered combustion engine works in a cyclical nature. The piston within the engines moves up and down (the top position the piston reaches is called TDC, meaning Top Dead Center, and the bottom-most position the piston touches is called BDC, Bottom Dead Center.) Then there are the valves. When a piston is in the TDC position, it is closest to the valves. When the piston moves into BDC position, it is furthest away from the valves. 

What is a Stroke?

A stroke is when the piston in an engine (mentioned above) moves from the TDC position to BDC position, or the other way around. Think of it as a swimming stroke: your arm glides through the water from the top of your body, downward, to propel your body through the water. A stroke in an engine is similar (in theory.)

The full combustion cycle entails gas and air being thrust into the piston, igniting it and then pushing out the exhaust. The critical difference between a 2-stroke engine and a 4-stroke engine is how fast the combustion cycle occurs.  This is directly determined by the number of times the piston moves up and down during a given cycle. 

A 2-stroke engine’s piston moves up and down only one time within the combustion cycle, whereas the 4-stroke engine’s piston moves up and down two times during its revolution.

PROS

  • Light Weight: a jet ski with a 2-stroke engine is going to feel a lot lighter and easier to manipulate than the 4-stroke engine
  • Easy to Repair: due to the 2-strokes simple design, a 2-stroke engine jet ski is going to be much easier to fix. This is ideal for the DIYer who prefers to repair their own motorized toys. 
  • More Powerful: The 2-stroke engine is made to run on higher RPMS, so it will have greater torque (and make for a fun, fast ride).

CONS

  • Loud: The 2-stroke jet ski is, unfortunately, going to have an audible high-pitched whizzing sound. 
  • Shorter Lifespan: Due to the 2-stroke engine having more torque in higher RPMs, this means the engine will wear out long before a 4-stroke engine will. The high RPMs take a heavy toll on a motor.
  • Requires Pre-mixing: A 2-stroke engine requires the pre-mixing of oil and fuel, whereas the 4-stroke engine does not
  • Causes Pollution: Unfortunately, the biggest down-side I’ve come across personally is that this type of engine is pretty terrible for our waters. Scientists estimate that about 20-25% of the fuel in a 2-stroke engine does not combust, which means it is left to leak into the body of water it is submerged in. That means raw fuel seeps into our beloved lakes and rivers. In 2019, given our current global climate crisis, this information alone is enough for me to say no to a 2-stroke engine. Learn more here.
  • Less Readily Available: Due to certain jet ski manufacturers no longer selling 2-stroke jet skis, you will likely have an easier time purchasing a new 4-stroke. However, you will be able to find many used 2-stroke jet skis (they just likely will not come with a warranty).

The 4-Stroke Jet Ski Engine

PROS

  • Efficiency: considering the fact that the fuel in this type of engine is being consumed every four strokesthe 4-stroke engine is by far more efficient. This type of motor is used more frequently in larger vessels (like a jet ski), whereas you can find a 2-stroke engine in smaller items, like a chainsaw.
  • Less Noisy: the 4-stroke engine is naturally going to be quieter than your 2-stroke engine.
  • More Environmentally Friendly: while any motorized craft will inevitably pollute in some form or another, the 4-stroke jet ski will effectively be 30% more environmentally friendly than its 2-stroke counterpart.
  • More Durable: While the 2-stroke engine may be more powerful, the 4-stroke engine is more durable and has better longevity
  • New & Available: Since most new jet skis today are 4-stroke, they are going to be more readily available and easy to find. If you purchase new, most retailers will provide you with a 5-year warranty.

CONS

·      Heavy: A 4-stroke engine is going to be nearly 50% heavier than a 2-stroke engine, and depending on the rider and their skill sets/needs, this could make a big difference. (The Kawasaki brand 4-strokes is likely to be the lightest 4-stroke option on the market

·      More Expensive: The 4-stroke engine jet ski has more parts (including valves), and the repairs cost more than the 2-stroke engine. However, these out of pocket costs shouldn’t be too much of a concern when you first purchase, as your craft will be under warranty (if you purchase it new).

The Takeaway?

Truthfully, you are likely to have an insane amount of fun on either a 2-stroke jet ski or a 4-stroke. The watercraft of your choice really depends on your individual needs. If you are looking for something cost-effective, then you may want to purchase a used 2-stroke (just be aware that you may need to repair it more frequently – and that could potentially cost you $500-1000 per repair).

If you desire something that is new, ready to go, and under warranty, you’ll want to purchase a 4-stroke jet ski at your local retailer. Here are 10 things to look for when buying a used jet ski.

The Top 5 Jet Skis for 2020

Top Jet Skis and PWCs 2020

To assist you in your personal watercraft hunt, I’ve sourced the top 5 jet skis to purchase in 2020. The prices are approximate—actual prices will vary on a number of factors.

1.    Sea Doo Spark Trixx – ($7,500)
As its name suggests, this water-bike is perfect for performing cool tricks. It has a step wedge, which will ensure you feel more stable when you stand in different positions on your jet ski. The adjustable steering is also a huge plus for the trickster water-biker.

2.    Kawasaki Jet Ski SX-R – ($10,000)
Another hot commodity in the stand-up jet ski department is this latest Kawasaki SX-R. It’s an excellent 4-stroke bike with rider-active steering & handling. This watercraft is excellent for a broader range of riders – not just pros.

3.    Yamaha WaveRunner VX Ltd. – ($11,200)
This WaveRunner is the latest and greatest from Yamaha, with the high powered 4-stroke engine, and multiple features like the 40 liter storage compartment, weather resistant foam and a compatible cooler (I mean, how cool is that?)

4.    Sea-Doo Fish Pro – ($14,800)
Why this is an industry first is beyond me, because it seems obvious to use a jet ski for fishing! Since this is a small personal fishing vessel, it comes with an 11.5 extended platform on the back to allow for more space for when you’re loading up all your catch!

5.    Kawasaki Jet Ski Ultra 310X ($15,300)
This bad boy comes with three seats and is so multipurpose that you can take it out racing on the ocean, or you can do a chill, comfortable leisurely ride on a lake. It has a supercharged engine just in case you’re feeling feisty – and is likely to outperform all its competitors in comfort and versatility.

Final Thoughts

Most new jet skis sold today have 4-stroke engines.  And the market for specialty accessories has grown to the point you can outfit your ski for all different types of use. Regardless of engine size, the goal is to have fun, and when you’re riding your jet ski, you won’t be thinking about the number of strokes, but how much fun you’re having.

Articles contain affiliate links to Amazon. As an Amazon Associate we earn from qualifying purchases. The site is also an affiliate for other brands covered in our the content. We may earn a small commission when readers purchase through these links at no extra cost to the buyer.

 

Tim Conner, M.D.

Tim Conner, M.D. started boating in 1974. He has been involved in recreational boating continuously since then. Dr. Conner has been active in boating and watersports safety education for decades. He rode his first jet ski in 1997, and rejoined the personal watercraft arena in 2012 with a Sea-Doo GTX 155, followed by 2 supercharged SeaDoos. Scuba certification came in 1988, and he and the family have traveled the world snorkeling and scuba diving for decades. The family has recently taken up paddle boarding. Click the photo for a lot more.

Recent Content