2004-2005 Kawasaki STX-15F Jet Ski Factory Service Manual., Page 421Get this manual
16-32 APPENDIX Troubleshooting Guide
Spark plug cap shorted or not in good contact IC igniter in ECU trouble Camshaft position sensor trouble Crankshaft sensor trouble Wiring shorted or open Fuse blown Fuelair mixture incorrect Air passage clogged Air ilter poorly sealed Fuel injector trouble Water or foreign matter in fuel Throttle sensor trouble Fuel pressure may be low Fuel pump trouble Inlet air pressure sensor trouble Inlet air temperature sensor trouble Water temperature sensor trouble Crankshaft sensor trouble Compression Low Spark plug loose Cylinder head not sufficiently tightened down No valve clearance Cylinder, piston worn Piston ring bad (worn, weak, roken, or sticking) Piston ringgroove clearance excessive Cylinder head gasket damaged Cylinder head warped Valve spring broken or weak Valve not seating properly (valve bent, worn, arbon accumulation on the seating surface)