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1999-2005 Kawasaki Ultra 150 Review and Specs [Video]

1999-2005 Kawasaki Ultra 150 Review and Specs [Video]

The Kawasaki Ultra 150 was a more advanced configuration of the 2-seater 1100 ZXi, which was manufactured from 1999 through 2005. It was built on a modified ZXi hull but had a more powerful, 1176cc, triple engine rated at 145 HP. Thanks to its outstanding performance and handling, the Ultra 150 won numerous championships around the Millennium.

If you want to find out more about this race-ready Kawasaki Jet Ski, this post is for you.

We at JetDrift have compiled all you need to know into this Kawasaki Ultra 150 review!

1999-2005 Kawasaki Ultra 150 Review

Kawasaki Ultra 150 Hull and Top Deck

Kawasaki introduced its popular ZXi series in 1995 as its high-performance 2-seater runabout line. This series included the base 750 ZXi, 900 ZXi, and high-end 1100 ZXi.

The Japanese manufacturer released the flagship Ultra 150 in 1999, as the most powerful Kawasaki Jet Ski. Due to its 1200 engine, this model was often referred to as the Kawasaki Ultra 1200 as well.

Although it wasn’t officially a member of the ZXi family, the platform of the Ultra 150 was based on the proven ZXi hull.

To handle the increased performance, the platform was slightly lengthened and widened.

Regarding dimensions, the Ultra 150 was 113.8 inches long, 44.4 inches wide, and 40.5 inches high. This means that the Ultra was 5.1 inches longer and 2.3 inches wider than standard ZXi models.

It also featured a 22-degree deep-V deadrise, which stretched from the front toward the intake. This sharp entry could easily cut through the chop while the integrated spray deflectors effectively protected you from the water spray.

Keeping precise handling in mind, the ski was equipped with a pair of high-performance sponsons. It also featured a 2-rider seat and special padded handlebars to increase safety.

In terms of materials, the Ultra 150 was made of hand-laid fiberglass and strengthened by bulkheads, translating to a lightweight construction with less structural flex. This innovative “bulkhead construction” hull offered great cornering abilities.

On the other hand, it suffered from a more intense water drag, which negatively affected the speed. Fortunately, this was compensated for by a much more powerful engine.

Let’s get down to the nitty-gritty and talk about this amazing 2-stroke Kawasaki triple in detail!

Kawasaki Ultra 150 Engine and Propulsion

The engine of the Kawasaki Ultra 150 was a 2-stroke, 1176cc, triple-carbed, 3-cylinder Kawasaki marine engine. Despite the ‘150’ tag in the model name, the engine of the Ultra 150 delivered a maximum power of 145 HP at 6,750 RPM with a maximum torque of 113 pound-foot (153.5 N.m).(The Ultra was also marketed with a 130 HP, fuel-injected engine option under the name of Ultra 130 D.I.)

The power mill of the Ultra was also known to be the carbed 1200 Kawasaki Jet Ski engine, which had the following characteristics:

  • 2-stroke, 3-cylinder architecture
  • Crankcase reed valve configuration
  • Triple Keihin CDCV40-35 carbs with single fuel pump
  • Variable-rate Superlube oil injection system
  • Compression ratio: 5.8:1
  • DC-CDI ignition
  • Kawasaki Throttle Responsive Ignition Control (K-TRIC)
  • Open-loop cooling system
  • Electric starter
The cylinders of this powerhouse were slanted 45 degrees in the hull and its intake manifold was also slanted back 45 degrees.

This configuration allowed the use of a more effective, downdraft carburetor position. What does this mean?

In a nutshell, a downdraft carburetor is mounted on top of the engine, so that air comes from above the carburetor and goes straight down through the intake.

The intakes of the Ultra 150 engine feature three Keihin CDCV constant velocity carburetors.

To keep the engine temperature low, each of the cylinders had a separate water jacket and utilized lightweight Nikasil plating.

For optimal ignition, the engine was also equipped with the innovative Kawasaki Throttle Responsive Ignition Control (K-TRIC), which continually monitored engine speed and throttle position via a set of sensors.

This system ensured a quicker throttle response, which translated to a more aggressive acceleration.

The 1999 Ultra 150 had a more advanced ignition system that required the very expensive NGK R6918C-9 spark plugs. Although this configuration offered a slightly faster speed, it didn’t compensate for the higher maintenance costs.

The 2000-2005 models utilized a simpler ignition feeding with more affordable BR9ES plugs.

In terms of lubrication, the Ultra 150 was engineered with an oil injection system, featuring a variable-speed oil pump. This advanced pump adjusted oil delivery based on the engine speed, resulting in less smoke and better oil consumption.

This engine was paired with the all-new mixed-flow jet pump, housing a 3-blade impeller that delivered a maximum thrust of 904 pounds.

The pump was positioned very low in the hull, which ensured a better hook-up and faster acceleration.

Another unique feature of the Ultra 150 was its water-jacketed dry exhaust system. In this system, the exhaust gases flowed completely dry since the cooling water was separate from the expansion chamber.

Since the exhaust fumes didn’t have to deal with restrictive water vapor, they could move on with less energy loss. Other hidden benefits of this dry exhaust were the lower temperature of the engine and exhaust components, as well as reduced engine noise.

The engine was attached to the hull via rubber mounts, which also reduced noise and vibration.

Despite its amazing 145 HP performance, the Ultra 150 wasn’t the most powerful PWC around the Millennium, since the Yamaha XL1200 delivered a whopping 155 HP. (On the other hand, the Ultra was 133 pounds lighter.)

Kawasaki Ultra 150 Features

Although the Ultra 150 had fewer bells and whistles than the luxury STX 1100 D.I., it came with many advanced features, including:

The storage compartments consisted of an under-seat storage case, a glovebox, and a standard bow storage, housing a removable bin and a fire extinguisher compartment.

The front hood featured a hydraulic lifting cylinder for easier opening.

The fuel and oil filler cap were also covered with this hood while the ignition switch was nestled under the glovebox lid.

The LCD instrument panel of the Ultra 150 had many useful functions, including:

  • Speedometer
  • Tachometer
  • Clock/Time/Trip/Hour meter display
  • Trim indicator
  • Fuel level gauge
  • Low fuel warning light
  • Water temperature symbol
  • Engine oil level gauge
  • Low oil warning light
  • Battery symbol
  • Check engine symbol

Kawasaki Ultra 150 Performance

The Kawasaki Ultra 150 was considered to be a motorcycle of the water and with good reason.

It was extremely fast, lightweight, and offered amazing cornering abilities. Although it was rated for two riders it was more of a solo machine.

Regarding performance numbers, the Ultra 150 could reach a whopping top speed of 64-65 mph in stock condition. With some aftermarket performance parts, it could be pushed into the ballpark of 75-80 mph!

Its remarkable power was matched with great stability and fast cornering abilities.

The claimed fuel consumption of the ski was 13.3 GPH at full throttle, so its 15.3-gallon fuel tank offered a fuel range of 75 miles or 1 hour and 9 minutes of fun.

One of the key features of the ski was its manually adjustable trim, which allowed you to adjust the vertical position of the jet nozzle based on water conditions. This system could be controlled by an electric variable trim adjustment switch mounted on the left handlebar.

The integrated Kawasaki Splash Deflector (KSD) reduced water spay, which meant dryer rides.

Although the Ultra was very popular among racers and performance-minded riders, some of them found its hull unpredictable, especially in rough water conditions.

It was prone to changing direction without any warning, resulting in some very surprising moments. Aftermarket ride plates and sponsons helped somewhat with these problems.

Kawasaki Ultra 150 Problems

Based on our research, the most common problems of the Kawasaki Ultra 150 were as follows:

  • No reverse bucket
  • Improper shut-off switch location
  • Short-lived pump bearings
  • Aging oil lines
  • The oil injection system was hard to remove
  • Expensive plugs in the ’99 model
One of the biggest flaws of the Ultra 150 was its lack of a reverse system.

While the more advanced 3-seater Jet Skis came standard with this important feature, the reverse was not available on the Ultra 150, even as an option.

Its trim button was also located too close to the shut-off valve, so there was always the risk that you would accidentally shut off the engine while adjusting the trim. As you can imagine, at higher speeds this was more than unpleasant!

Another problem with the Ultra 150 was that it ate its pump bearings very fast. In many cases, the bearings in its pump only lasted 25-30 hours!

The factory-installed oil lines are prone to getting brittle over time in many vintage Kawasaki Jet Skis, and the Ultra 150 was no exception.

Replacing these hoses was a fairly easy maintenance procedure, but eliminating the entire oil system was much more difficult on this model. This is because the oil system was intended to lubricate not only the cylinders but the crank as well.

Therefore, removing the entire oil system was not possible since it would leave the crank without any lubrication.

Last but not least, the ’99 model came with a more advanced ignition, which required much more expensive spark plugs.

Kawasaki Ultra 150 Specs Charts

For your convenience, we’ve compiled the key specs of the 2005 Kawasaki Ultra 150 into these charts:

Kawasaki Ultra 150 Engine Specs

Kawasaki Ultra 150Engine Specs
Engine type2-stroke, 3-cylinder, crankcase reed valve, water-cooled
Displacement1 176 mL (71.8 cu in.)
Bore and stroke80.0 x 78.0 mm (3.15 x 3.07 in.)
Compression ratio5.8 : 1
Ignition systemDC-CDI
Lubrication systemOil injection (break-in period: oil injection and gas/oil mixture 50:1)
CarburetorKeihin CDCV 40-35 x 3
Starting systemElectric starter
Battery12 V 18 Ah
Engine oil type2-stroke, NMMA Certified for Service TC-W 3
Engine oil tank capacity4.7 L, 5.0 qt (US)

Kawasaki Ultra 150 Tuning Specifications

Kawasaki Ultra 150Tuning Specifications
Spark Plug TypeNGK BR9ES
Spark Plug Gap0.7 ∼ 0.8 mm (0.028 ∼ 0.032 in.)
Spark Plug TerminalSolid post
Ignition Timing15° BTDC @1250 r/min (rpm) - 22° BTDC @3500 r/min (rpm)
Carburetor Idle Speed - in water1 250 ±100 r/min (rpm)
Carburetor Idle Speed - out of water1 800 ±100 r/min (rpm)
Compression Pressure970 kPa (9.9 kg/cm2) @ 440 r/min (rpm) - 141 psi

Kawasaki Ultra 150 Drive System

Kawasaki Ultra 150Drive System
CouplingDirect drive from engine
Jet Pump TypeMixed flow, single stage
Jet Pump - Thrust410 kg (904 lb)
SteeringSteerable nozzle
BrakingWater drag

Kawasaki Ultra 150 Performance

Kawasaki Ultra 150Performance
Minimum Turning Radius4.0 m (13.1 ft)
Fuel Consumption50.5 L/hr (13.3 US gal/hr) @full throttle
Cruising Range (1)109 km (68 mi) @full throttle
Cruising Range (2)1 hour and 7 minutes

Kawasaki Ultra 150 Dimensions

Kawasaki Ultra 150Dimensions
Overall length113.8 in (2 890 mm)
Overall width44.4 in (1 129 mm)
Overall height40.5 in (1 028 mm)
Dry Weight284 kg (626 lbs)
Fuel tank capacity15.3 US gal (58 L) including 1.8 US gal (7 L) reserve
These charts are for informational purposes only! For exact specifications, please refer to the factory manual.


As a takeaway, we’ve answered the most common questions about the 1999-2005 Kawasaki Ultra 150:

What is a Kawasaki Ultra 150?

The Ultra 150 was a high-performance, 2-seater Kawasaki Jet Ski, a more advanced configuration of the ZXi 1100.

When did the Kawasaki Ultra 150 Come Out?

The Kawasaki Ultra 150 debuted in 1999.

What Years Did Kawasaki Make the Ultra 150?

Kawasaki marketed the Ultra 150 from 1999 through 2005.

What Size was a Kawasaki Ultra 150?

The Kawasaki Ultra 150 measured 113.8 inches in length, 44.4 inches in width, and 40.5 inches in height.

How Much Did a Kawasaki Ultra 150 Weigh?

The dry weight of the Kawasaki Ultra 150 was 613 or 626 pounds depending on the model year (’99-’02: 613 lbs, ’03-’05: 626 lbs).

How Many People Could Ride on a Kawasaki Ultra 150?

The Kawasaki Ultra 150 was rated for two riders.

What Kind of Engine was in the Kawasaki Ultra 150?

The Kawasaki Ultra 150 was powered by a 2-stroke, triple-carbed, 1176cc Kawasaki marine engine.

Was the Kawasaki Ultra 150 Supercharged?

The Kawasaki Ultra 150 utilized a naturally-aspirated engine configuration.

Was the Kawasaki Ultra 150 a 2-stroke?

Yes, the Kawasaki Ultra 150 was powered by a 2-stroke engine.

Was the Kawasaki Ultra 150 Fuel Injected?

No, the Kawasaki Ultra 150 featured three Keihin CDCV 40-35 carburetors.

How Much Horsepower Did a Kawasaki Ultra 150 Have?

The Kawasaki Ultra 150 produced 145 HP in stock condition.

How Much Oil Did a Kawasaki Ultra 150 Hold?

The Kawasaki Ultra 150 had an oil injection system featuring a 5.0-quart oil tank.

How Much Fuel Did a Kawasaki Ultra 150 Hold?

The Kawasaki Ultra 150 was equipped with a 15.3-gallon fuel tank.

How Much Fuel Did a Kawasaki Ultra 150 Use?

The claimed fuel consumption of the Kawasaki Ultra 150 was 13.3 GPH at full throttle.

What was the Fuel Range of the Kawasaki Ultra 150?

The claimed fuel range of the Kawasaki Ultra 150 was 75 miles or 1 hour and 9 minutes at WOT.

How Much Weight Could a Kawasaki Ultra 150 Hold?

The total weight capacity of the Kawasaki Ultra 150 was 330 pounds.

How Fast Did a Kawasaki Ultra 150 Go?

The top speed of a Kawasaki Ultra 150 was about 64-65 mph under ideal conditions.

Could the Kawasaki Ultra 150 Tow a Skier or a Wakeboarder?

Due to its two-seater configuration, the Ultra 150 couldn’t legally tow a wakeboarder or skier in states where a spotter was required.

Did the Kawasaki Ultra 150 Have a Reverse?     

No, the Kawasaki Ultra 150 came without a reverse system.

Did the Kawasaki Ultra 150 Have a Brake?         

No, the Kawasaki Ultra 150 was manufactured without a brake system.

How Much Does a Kawasaki Ultra 150 Cost?

The asking price of a used Kawasaki Ultra 150 varies between $1,000 and $5,000 depending on the year and its condition.