1990-1991 Sea-Doo GT Specs and Review [Video]

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The 1990 Sea-Doo GT was the first 3-seater Sea-Doo in history. It shared its engine and pump with the lively XP, but it was built on a larger, flat-bottomed hull.

If you want to learn all about this iconic PWC, this post is for you.

We at JetDrift have compiled all you need to know into this Sea-Doo GT review!

1990-1991 Sea-Doo GT Review

The first “modern” Sea-Doo, the popular SP made its debut in 1988. This model was then carried over for the 1989 model year without any significant changes.

However, by 1990 the Sea-Doo fleet had been expanded to include a new model, namely the Sea-Doo GT.

As its name suggests, this ski was larger, featuring a roomier seat and more expansive capacities.

Although the manufacturer advertised the GT as a three-seater model, riding it with two adult passengers was virtually impossible.

Its tiny composite hull measured only 119.3 inches in length, 47.6 inches in width, and 37.4 inches in height. (In contrast, the SP hull was 96 inches long and 41.5 inches wide.)

The GT wasn’t significantly more stable than its smaller brothers despite its extended dimensions. The total load limit of the machine was only 496 pounds, with a dry weight of only 461 pounds.

Fully loaded, the GT became very tippy, especially at lower speeds. Therefore, this model was considered a two-seater ski rather than an authentic three-seater.

What’s more, it featured a smooth-bottom hull, which came without sponsons. As you can imagine, this setup provided very minimal traction in the corners. On the other hand, it could spin really nicely!

The engine of the 1990 Sea-Doo GT was the dual-carb “Yellow” Rotax 587 engine. This 580cc two-stroke twin utilized two Mikuni carburetors, CDI ignition, and an innovative oil-injection system.

Thanks to these advanced features, the Sea-Doo GT produced 55 HP at 5,750 RPM and a maximum torque of 51 lb.-ft. at 5250 RPM.

Engine power was delivered to an axial-flow, single-stage Bombardier Formula jet pump. This propulsion system housed a 139.5 mm stainless steel impeller, providing a maximum thrust of 504 lbs.

To feed the engine, the Sea-Doo GT was equipped with an 7.7-gallon gas tank and a 95 oz. oil tank. Both units were made of durable polyethylene.

The maximum fuel consumption of the ski was about 5 GPH at WOT, so its fuel tank offered a cruising time of about one and a half hours.

Under ideal conditions and with a light load, the top speed of this vintage 2-stroke Sea-Doo was about 36 mph.

It should also be noted that the 1990 Sea-Doo GT was the first Sea-Doo equipped with a reverse system. This simple mechanical system utilized a reverse gate, which was operated by a reverse handle on the dashboard.

Another convenient feature of this machine was its 13.2-gallon storage bin, which could accommodate plenty of gear.

The Sea-Doo GT also came with many other useful features, including:

  • Electric start (std.)
  • Tether cord (std.)
  • Fuel tank reserve (std.)
  • Overheating warning device (std.)
  • Reverse (std.)
  • Storage compartment (std.)
  • Rear grab handle (std.)
  • Electric fuel level gauge (opt.)
  • Injection oil low-level warning device (opt.)

There’s no question that the key advantage of the Sea-Doo GT was its simplicity. Since it lacked complex electronics and systems, it was very easy to maintain. Its roomy hull also allowed plenty of space to work on the engine.

However, one of the few drawbacks of the machine was the awkward location of its battery.

The manufacturer carried over the Sea-Doo GT for the 1991 model year without any changes.

But by 1992, the GT had been renamed as GTS, and its hull got some strakes for better handling and stability. This revamped GTS remained in production until the 2000 season.

1990-1991 Sea-Doo GT Specs Chart

For your convenience, we’ve compiled the Sea-Doo GT specifications into these charts!

Sea-Doo GT Dimensions

Sea-Doo GTDimensions and Capacities
Number of passengers1 operator and 2 passengers
Overall length303 cm (119.3 in)
Overall width121 cm (47.6 in)
Overall height95 cm (37.4 in)
Weight209 kg (461 lb)
Load limit225 kg (496 lb)
Hull MaterialComposite (fiberglass)
Fuel tank29.1 L (7.7 US gal)
Impeller shaft reservoir - Capacity65 mL (2.2 US oz)
Impeller shaft reservoir - Oil level heightup to plug
Injection oil reservoir2.8 L (95 US fl oz)

Sea-Doo GT Engine Specs

Sea-Doo GTEngine Specs
Engine type Rotax 2-stroke, type 587
Induction type Rotary valve
Exhaust system Water cooled/water injected
Lubrication - type Oil injection
Lubrication - oil typeSea-Doo Injection Oil
Number of cylinders 2
Bore76.0 mm (2.992 in)
Stroke64.0 mm (2.520 in)
Displacement 580.7 cm3 (35.43 in3)
Compression Ratio (corrected)5.9 : 1
Maximum Power (approximately)41 kW (55 HP) at 5750 RPM
Maximum Torque (approximately)NA
RPM Limiter Operation @6500 RPM ± 200
Cooling TypeWater cooled, total loss type - Direct flow from propulsion unit
Overheating Beeper, Switch On @96-99 °C (205-210°F)

Sea-Doo GT Carburation

Sea-Doo GTCarburation
Fuel - typeRegular unleaded gasoline
Carburetor - type and numberDiaphragm type P/N 270 500 073 (MAG side)
Carburetor - type and numberDiaphragm type P/N 270 500 072 (PTO side)
Carburetor adjustments - Low-speed mixture screw~ 1- 1/2 turn
Carburetor adjustments - Idle speed1200 RPM

Sea-Doo GT Propulsion

Sea-Doo GTPropulsion
Propulsion systemBombardier Formula pump
Jet pump typeAxial flow, single stage
Impeller Rotation (seen from rear)Counter-clockwise
TransmissionDirect drive
Coupling TypeCrown Splines
Impeller shaft reservoir oil typeSea-Doo Jet Pump synthetic oil (P/N 293 600 011) polyolester 75W90 only
Pivoting angle of direction (nozzle)26°
Pivoting angle of variable trim systemN.A.
Minimum required water level for jet pump60 cm (2 ft)
Impeller Diameter139.5 mm (5.49 in)

Sea-Doo GT Electrical Features

Sea-Doo GTElectrical Features
Magneto generator output160 W @ 5500 RPM
Ignition system type Capacitor Discharge Ignition (Breakerless)
Spark plug - Make and typeChampion RN4C
Spark plug - Gap0.6 mm (0.024 in)
Starting systemElectric starter
Ignition timing - BTDC2.18 mm (0.086 in) (19 ° ± 2°)
Ignition timing - NoteChecked with engine cold. Marks must align @ 6000 RPM)

Sea-Doo GT Performance

Sea-Doo GTPerformance
Horsepower55
Cruising time at full throttle - Fuel tank without reserve~ 1.5 hours
Cruising time at full throttle - Fuel tank reserve~ 15 minutes
Maximum Speed *58 Kmh (36 mph)
* Top speed may vary depending on operator and passenger weight, water conditions, wind, current, altitude etc.

These charts are for informational purposes only! For exact specifications, please refer to the factory manual.

Vintage Sea-Doo GT For Sale

If you are considering purchasing one, you probably want to know where to find a Sea-Doo GT for sale. As this model vanished from the market in 1992, it’s already a collectible item, so finding one is not an easy task!

We recommend that you start your research on dedicated Sea-Doo forums and Facebook fan groups. Aside from some good deals, you may find some valuable info there about this ski.

Besides these sources, you may also find some used Sea-Doo GTs for sale on Craigslist, PWC Trader, and other dedicated jet ski swap sites.

Takeaway

As a takeaway, we’ve answered the most common questions about the Sea-Doo GT!

What is a Sea-Doo GT?

The Sea-Doo GT was the first 3-seater Sea-Doo manufactured by BRP.

What Year did Sea-Doo Make the GT?

Sea-Doo marketed the Sea-Doo GT from 1990 through 1991.

How Many People Could Ride a Sea-Doo GT?

The tiny Sea-Doo GT was rated for three riders, but riding it with adult passengers was virtually impossible!

What Size was the Sea-Doo GT?

The Sea-Doo GT was 119.3 inches long, 47.6 inches wide, and 37.4 inches high.

How Much Did a Sea-Doo GT Weigh?

The dry weight of the Sea-Doo GT was only 461 pounds.

How Much Weight Could a Sea-Doo GT Hold?

The total weight capacity of the Sea-Doo GT was 496 pounds.

What Kind of Engine Did the Sea-Doo GT Have?

The engine of the Sea-Doo GT was the dual-carb “Yellow” Rotax 587, featuring CDI ignition, electric start, and an oil injection system.

How Much Horsepower Did a Sea-Doo GT Have?

The Sea-Doo GT provided 55 HP at 5,750 RPM.

Did the Sea-Doo GT Have Reverse?

Yes, the Sea-Doo GT was equipped with manual reverse.

What Size Storage Compartment Did a Sea-Doo GT Have?

The Sea-Doo GT featured a 13.2-gallon front storage compartment.

How Much Fuel Did a Sea-Doo GT Hold?

The Sea-Doo GT utilized an 7.7-gallon polyethylene fuel tank.

How Much Fuel Did a Sea-Doo GT Use?

The Sea-Doo GT fuel consumption was about 5 GPH at WOT, resulting in a cruising time of 1.5 hours.

Could the Sea-Doo GT Tow a Skier or a Wakeboarder?

The Sea-Doo GT was rated for three riders, so it could legally tow a skier. However, towing this machine was tricky due to its unstable hull and underpowered engine.

How Fast Did a Sea-Doo GT Go?

The top speed of a Sea-Doo GT was 36 mph in stock condition, but with some aftermarket mods, it could easily hit 38-40 mph.

Was a Sea-Doo GT a 2-Stroke Ski?

Yes, the Sea-Doo GT utilized a 2-stroke twin engine.

How Much is a Sea-Doo GT Worth?

It’s hard to tell the exact price of a Sea-Doo GT, as it strongly depends on its year, condition, and location. But as a rule of thumb, the prices typically range from $300 up to $1,500.

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