1988-1992 UltraNautics JetStar 1250 Specs and Review [Video]

The UltraNautics JetStar 1250 was one of the smallest 2-stroke mini jet boats manufactured from 1988 through 1992. This tiny 3-passenger runabout was built on an extremely small, 12.5-foot fiberglass hull and could be opted with either 50, 60, or 90hp jet engine options.

In this post, we’ll take a close look at this vintage mini jet boat and its key specifications.

UltraNautics JetStar 1250 Review

Hull and Deck

The JetStar 1250 was often referred to as the “sports car of the water,” and with good reason.

At first glance, it looked like a coupe sports car, and its performance wasn’t bad either, especially with the 90hp engine option.

As the name suggests, the 1250 utilized a tiny fiberglass hull measuring 12.5 feet in length and 5.75 feet in width.

With the jet pump assembly and fittings, the overall length of the vessel was only 13.1 feet.

The dry weight of the JetStar 1250 was only 615 pounds with the standard 50hp engine package and with no optional features.  With a more advanced engine and optional features, its dry weight increased into the range of 650-700 pounds.

The “car-like” driving experience of the 1250 was further enhanced with its unique left-hand drive setup. (Unlike cars in the U.S., the majority of boats have the steering wheel on their right or “starboard” side).

In return, the driver had to operate the throttle/shift lever with his/her left hand.

The tiny cockpit of the 1250 was equipped with an informative dashboard placed in the middle.

Its flat bench seat was rated for three people and its starboard side could be switched to face toward the rear.

This versatile design was a game changer for tow sports lovers since the spotter could comfortably watch the skier/wakeboarder from this seat.

Thanks to a passage to the stern and the large fold-up swim ladder the 1250 was very easy to reboard. This was a very interesting solution on this tiny deck since this design is typically more prevalent on larger boats.

In terms of capacities, the boat could carry 3 people, 12 gallons of fuel, and a limited amount of gear up to a 495-pound total weight capacity.

It also had a storage compartment next to the engine bay and a glovebox in the cockpit.

Engines

As a rule of thumb, the UltraNautics JetStar 1250 was manufactured with three different engine packages, the 50hp Suzuki twin, 60hp Suzuki twin, and 90hp Mercury SportJet 90 triple.

Each of these was a 2-stroke, carbureted, reed-valve marine jet engine with an outboard powerhead. They came without an oil injection system and featured a manual reverse.

To be more precise, the key features of these different engine packages were as follows:

50hp, Suzuki twin:

• Architecture: In-line, twin-cylinder
• Powerhead: Suzuki outboard
• Displacement: 798cc
• Bore x stroke: 80 x 72 mm
• Compression ratio: 6.1:1
• Performance: 50hp
• Carburetors: 2 x Mikuni
• Lubrication: Premix

60hp, Suzuki twin:

• Architecture: In-line, twin-cylinder
• Powerhead: Suzuki outboard
• Displacement: 798cc
• Bore x stroke: 80 x 72 mm
• Compression ratio: 7.0:1
• Performance: 60hp
• Carburetors: 2 x Mikuni
• Lubrication: Premix

Mercury Sport Jet 90 triple:

• Architecture: In-line, 3-cylinder
• Powerhead: Force outboard
• Displacement: 1231cc
• Bore x stroke: 86 x 71 mm
• Performance: 90hp
• Carburetors: 3
• Lubrication: Premix

The 60hp Suzuki was literally an upgraded version of its 50hp predecessor, as they shared the same 798cc, twin-cylinder Suzuki outboard powerhead.

They also shared the same axial-flow, single-stage propulsion system utilizing a manual reverse bucket and a 4-blade, stainless steel impeller.

The lesser-known WetBike and SeaFlash PWCs also utilized the same propulsion system and Suzuki engine. (Both were manufactured by UltraNautics, too).

In contrast, the high-end Mercury SportJet 90 had a different architecture, housing a 90hp Force outboard powerhead.

This engine was paired with an axial-flow, mixed-stage pump housing a 5-blade impeller, and a manual reverse. Interestingly, this propulsion system was designed without a wear ring.

(Bayliner also used this engine and pump in its Jazz 1400 jet boat.)

The JetStar 1250 was also available with an outboard engine configuration under the name of UltraNautics Prostar. It was lighter and more lively than its jet-powered variant.

Features

When the JetStar 1250 was launched in 1988 many of its convenience features came as options.

In the following model year, these bells and whistles, like a glovebox, audio system, and trim became standard equipment, just like the galvanized trailer.

In a nutshell, the most important features of the JetStar 1250 were as follows:

• Navigation lights
• Tinted windshield
• Storage compartment
• Insulated ice chest
• Glovebox
• Foldable reboarding ladder
• Trim
• Drain plug
• Mooring cleats
• Stainless steel bow/transom eyes
• Fuel tank, built-in 12 gallons
• Fire extinguisher
• Snap-open gas cap
• Bilge blower
• Bilge pump

Helm station:

• Speedometer
• Tachometer
• Fuel gauge
• Voltage indicator
• Engine controls: side-mount, forward and reverse, with a neutral safety switch
• Ignition safety switch with lanyard
• Steering wheel
• AM/FM stereo radio/cassette player
• Switch console (lights, bilge pump, bilge blower, accessory switch)
• Fuses

On top of that, this boat came standard with a tiny galvanized trailer.

Riding Experience

Even though the JetStar wasn’t the fastest boat on the lake, it was a lot of fun to ride.

Thanks to its small lightweight moderate-V hull, it literally turned on a dime and was capable of thrilling spins.

Its unique, “PWC-like” riding experience made this boat highly desirable, contributing to the rapid rise in popularity of mini jet boats.

You could expect the top speed of the UltraNautics JetStar 1250 to be about 28-30 mph with the 50hp engine, and 33-35 mph with the 60hp power source. With the most powerful 90hp Merc Enigne the top speed of this boat could exceed the 40 mph barrier under ideal conditions.

As a comparison, the rival Bayliner Reflexx topped out at 33-35 mph with the same 90hp Merc. Sure it was a larger and heavier boat.

Problems

Even though the JetStar 1250 was fairly popular, it had some common problems and design flaws which were as follows:

Engine reliability

Unfortunately, the outboard powerheads of the Suzuki and Merc. 90 jet engines proved to be quite unreliable, especially compared to the rival Yamaha jet boats.

Poor performance

The 50 and 60hp engine variants only propelled this tiny boat to 30-35 mph, which was not a worthy speed for this sport boat.

What’s more, if you took a close look at the pump, you could find a center vein at the end of the steering nozzle. This vain was intended to restrict the thrust on one side when the boat was turning.

This feature made the boat safer in the corners but also reduced the fun factor.

Limited capacities

Due to its small cockpit and closed-bow design, the JetStar 1250 offered very limited seating and storage capacities.

It also had literally zero free deck space to move around.

Poor rough water performance

Due to its small hull featuring a shallow deadrise, the 1250 was very uncomfortable to ride on anything but glass-like water.

UltraNautics JetStar 1250 Specs Charts

For your convenience, we’ve compiled the key specs of this boat under one roof:

Dimensions and Capacities

Hull Type	Medium V
Hull Material	Fiberglass
Overall Length	13’ 3”
Hull Length	12’ 6”
Hull Width	5’ 9”
Height	2’ 8”
Dry weight*	615 lb.
Seating capacity	3 adults

*1988 model w/std DT50 engine and w/o optional accessories.

Engine Specs

Engine Opt.	Suzuki, 50hp	Suzuki, 60hp	Mercury Jet Sport 90
Architecture	Inline-2	Inline-2	Inline-3
Type	2-stroke	2-stroke	2-stroke
Number of Cylinders	2	2	3
Displacement	798cc	798cc	1231 cm³
Bore x stroke	80 x 72mm	80 x 72mm	85.7 x 71.1 mm
Compression ratio	6.1:1	7.0:1	Na.
Performance	50hp	60hp	90hp
Lubrication System	Pre-mix (50:1)	Pre-mix (50:1)	Pre-mix (50:1)
Number of Carburetors	2	2	3
Intake System	Reed valve, Loop charged	Reed valve, Loop charged	Reed valve
Choke system	Electric	Electric	Electric
Ignition System	CDI	CDI	C.D. Breakerless Magneto
Ignition system	8° BTDC @ 1000 RPM 28° BTDC @ 5000 RPM	Na.	Na.
Spark plugs	NGK BR7HS	Na.	Na.
Spark plug gap	0.8-0.9 mm (0.021-0.035in)	Na.	Na.
Battery	12V	12V	12V
Starting system	Electric	Electric	Electric
Cooling System	Forced water intake	Forced water intake	Thermostatic and pressure-controlled

Drive Unit*

Propulsion System	Jet pump
Jet Pump Type	Axial flow, single stage
Transmission	Neutral and Reverse Thrusts
Impeller Type and Size	Stainless steel, 187mm (7.3 in)

*1988 model

Fuel and Oil

Recommended Gasoline	85 minimum octane regular leaded
Lubrication	Pre-mix (Gasoline and oil mixing ratio 50:1)
Fuel tank capacity	12 US gal
Jet pump	SAE 490 Hypoid Gear Lubricant

These specifications are for informational purposes only. For further information, please refer to the operator’s manual.

Looking for an UltraNautics JetStar 1250 For Sale?

Even though this boat was only marketed from 1988 through 1992, many of them still appear on the used market.

If you are considering buying one, you can find many JetStar 1250 for sale on eBay, Craigslist, classified boat sites, and online jetboat forums. Asking prices can range anywhere from $500-$3,000 depending on the engine package and the condition.

If you are looking for a project boat, you can get one for a few hundred dollars, even with a trailer.