The MT-IGN-REV 99-02 RACER rev-limiter was designed for ALL 1999-02 Sea•Doo watercraft with 951cc R.A.V.E. engines only. (Carbureted Models ONLY) The curves below are designed to enhance the timing curve that you have chosen to use for your watercraft engine. You can add timing retard with Retard Tables 2-4 or leave the timing curve as-is by using Table # 1 (No Timing Retard)