Kawasaki JL650-A1 / SC Jet-Ski 1991 Service Manual (P/N 99924-1149-01)

• Exact application: Covers the 1991 Kawasaki JET SKI SC, model JL650-A1, with beginning hull identification listed as KAW9001[variable digit]191 or JL650A-600001. This is a 187-page PDF of Kawasaki Part No. 99924-1149-01.
• Engine repair coverage: Documents engine removal and installation, top-end disassembly and assembly, compression and wear inspection, crankcase splitting, coupling and magneto service, and crankshaft condition checks for the water-cooled vertical-twin two-stroke.
• Fuel, oil, exhaust, and cooling work: Covers the Keihin CDK38-32 carburetor and fuel pump, reed-valve intake, oil-injection pump bleeding and performance testing, exhaust joint and water-box service, plus cooling- and bilge-system inspection and flushing.
• Drive and jet-pump procedures: Includes drive-shaft and holder removal, bearing and seal replacement, shaft runout inspection, jet-pump disassembly and assembly, impeller inspection, and pump-clearance checks.
• Steering, reverse, and hull service: Details steering cable adjustment, wheel and shaft service, latching-mechanism work, shift-cable adjustment, reverse-bucket removal, engine-hood hardware, hull fittings, bumpers, and hull replacement.
• Electrical diagnosis: Provides battery test-charging guidance, starter-motor disassembly and inspection, charging-coil and regulator/rectifier tests, CDI and exciter-coil checks, switch and fuse inspection, and the system wiring diagram.
• Factory reference data: Supplies chapter-opening exploded views, cable and hose routing, torque and locking-agent information, wear limits, clearances, electrical test specifications, maintenance schedules, storage procedures, and symptom-based troubleshooting charts.

This factory service manual is specific to the JL650-A1 SC configuration. The general specifications identify a 635 mL, crankcase-reed vertical twin with oil injection, magneto CDI ignition, electric starting, direct engine-to-pump drive, a single-stage axial-flow jet pump, a steerable nozzle, and a reverse bucket. Kawasaki states that the manual is designed primarily for trained mechanics in a properly equipped shop; experienced owners with basic mechanical knowledge, correct tools, and workshop-procedure skills can also use it for basic maintenance and repair.

Engine, Fuel, and Cooling Work

The engine chapters go well beyond tune-up data. They cover engine-bed installation and shimming, coupling-damper inspection, piston and ring assembly, compression testing, cylinder-head warp, cylinder wear, piston-to-cylinder clearance, boring and honing, and piston-ring condition. Bottom-end diagnosis includes connecting-rod bend and twist, big-end radial and side clearance, main-bearing condition, crankshaft runout, and crankshaft assembly specifications.

Fuel-system repair includes cable adjustment, carburetor removal and internal disassembly, mixture and high-altitude adjustment, float-arm inspection, fuel-pump diaphragm service, reed-valve inspection, fuel-tank cleaning, vent-check-valve testing, and fuel-tap service. Separate chapters address oil-pump bleeding and output testing, exhaust-pipe and manifold cleaning, expansion-chamber and water-box work, cooling hoses, bilge filtration, and system flushing.

Propulsion, Controls, and Electrical Diagnosis

The drive and pump sections document seal and bearing work inside the drive-shaft holder and jet pump, along with shaft runout, impeller condition, pump-case wear, and impeller clearance. Steering coverage extends from the cable, wheel, shaft, and arm through the latching mechanism and steering frame. The reverse section adds shift-cable adjustment and inspection plus reverse-bucket removal and installation.

Electrical repair is supported by a color-coded Wiring Diagram and component tests for the battery, starter relay, reduction gear, starter motor, charging coil, regulator/rectifier, CDI igniter, exciter coil, spark plugs, switches, and fuse. The appendix traces starting failure, immediate stalling, misfire, abnormal engine noise, low power, jet-pump performance loss, and poor steering control to likely fuel, ignition, lubrication, compression, pump, or steering faults.

Reference Material, Tools, and Scope

Visual references include the Fuel System Diagram, Cable, Wire and Hose Routing views, Pump and Impeller Exploded View, Electrical System Wiring Diagram, and Battery Troubleshooting Guide. Tool callouts identify items such as Piston Pin Puller Assembly 57001-910, Flywheel Holder 57001-1313, Magneto Puller 57001-259, Impeller Wrench 57001-1228, and Hand Tester (V.O.M.) 57001-983.

During top-end repair, removed piston-pin snap rings must not be reused because a weakened ring can come loose and score the cylinder wall. Pump installation has a different trap: excess sealant near the impeller leading edges can obstruct water flow and induce cavitation. When the engine is run ashore, water entering a stopped engine can flow back through the exhaust, flood a cylinder, and cause hydraulic lock or other severe internal damage; inadequate cooling can also damage the engine and exhaust system.

The crankshaft section provides inspection and rebuilding specifications, but it expressly does not cover crankshaft disassembly because specialized equipment is required; Kawasaki directs that work to a properly equipped shop or calls for replacement of the complete assembly. This PDF is a service manual rather than a parts catalog, and it references separate Parts Catalog and Special Tool Manual publications. The title page carries © Kawasaki Heavy Industries, Ltd., 1991 and identifies this printing as First Edition (2), May 28, 1998 (K).