2003 Ski-Doo ZX Series Factory Shop Manual, Page 74Get this manual
Section 03 TROUBLESHOOTING Subsection 02 (ENGINE)
SYMPTOM CONDITION TESTINSPECTION
ENGINE EQUIPPED WITH RAVEENGINE HESITATES AT LOW OR MID-SPEED AND REACHES MAXIMUM PERFORMANCE ONLY AFTER WHILENORMAL USE1Check RAVE valve spring(s)aSpring tension is too low or spring(s) is (are) brokenReplace2Check RAVE valve cover red adjustment screwsaAdjustment screw(s) is (are) too looseAdjust according to ASSEMBLY PROCEDURE in appropriate engine subsections3Check RAVE valve movement (RAVE movement indicator PN 861 725 800)aValve(s) is (are) stuck in open positionClean