This manual covers the Yamaha WaveRunner LX / Jammer, a model from the 1st Generation WaveRunner Series produced in 1990. Designed for recreational watercraft use, this model features a robust 633 cc 2-stroke, 2-cylinder, water-cooled engine with a Mikuni carburetor fuel system. Its engineering emphasizes reliability and performance, offering a compact and agile platform for up to two occupants. The direct drive jet pump system with a 3-blade impeller ensures efficient propulsion, making it a capable personal watercraft for its era.

The purpose of this English-language Service Repair Manual is to provide comprehensive guidance for the maintenance and repair of your Yamaha WaveRunner. It details essential procedures, technical specifications, and troubleshooting steps necessary to keep the watercraft in optimal condition. Covered topics include engine specifications, lubrication, fuel system details, ignition system information, and dimensions. This manual is an indispensable resource for owners, mechanics, and technicians seeking to understand and maintain the operational integrity and longevity of the 1990 Yamaha WaveRunner LX / Jammer.