1994 Seadoo GTX

Specifications

Engine: Rotax 657, 2 cylinder,2 stroke
Displacement: 650cc
Horsepower: 70
Top speed: 68 km/h
fuel consumption: 50L/100km

Engine area

Jet pump area

Driveshaft area

Fuel system

The machine had the original gray fuel lines when I bought it. For some reason, a dark green goo forms wherever it comes in contact with brass fittings. This goo restricts the fuel flow and can cause the engine to bog down and stop. I changed the lines and cleaned out the fittings. The worst was the fuel selector valve. I got the line from Seadoo Alley.

The goo forms when the grey hose, brass fitting, and the ethanol in the fuel come into contact. Ethanol contributes to this in two ways. First, it causes the hose material to decompose. Then, it combines with the resulting breakdown products and the copper in the brass fitting to form the goo.

The fuel gauge wasn't working. The problem turned out to be the float. It wouldn't float anymore. I replaced it with an improved version that I got from Blinn Marine.

Ignition System

The ignition system consists of the magneto (front flywheel and upper coil), the ignition module (CDI and coil) and sparkplugs. The MPEM has the ability to stop the engine and limit the engine speed.

Magneto and Ignition Module

The upper coil in the stator supplies power and spark timing to the ignition module. There are magnets embedded in the flywheel. The ignition module fires both plugs at the same time.

Spark plugs

NGK BR8ES

B = 14mm thread diameter
R = Projected insulator
8 = heat rating: 10 is the coldest, 2 is the hotest
E = 19mm(3/4') reach
S = Standard center electrode

Gap: 0.5mm(0.02") (How to set the gap)

I've been finding that the spark plugs need to be changed several times a season. As they age the engine get's harder to start when the engine is cold. Old plugs work fine when the engine is warm.

Electrical system

New starter relay
part number 278 003 012

Shop manual

Exhaust system

Navigation Lights

Hull repair

Evercoat Formula 27 Filler - Like bondo but for boats
Evercoat Premium Gel-Kote, white - Has the consistancy of thick house paint. The fumes are very strong
Evercoat Mold release - spray over the last coat of gel-coat

Parts

Winners Circle
Large selection and fast delivery
Markham Ontario (near Toronto).

Kimpex
Drummondville (east of Montreal)

Motorsport World
Ottawa
613-832-1414

Service

On machines that are more than 10 years old it's very difficult to find garages to work on them. Here's what I found around eastern Ontario:

Seadoo Alley
Brockville
613-802-8540
A 2 week backlog is common

Blinn Marine
St. Lazare, Quebec (W of Montreal)