1992-1998 Kawasaki PWC Jet Ski Service Repair Manual., Page 52Get this manual
FUEL SYSTEM
ing knockIf the noise disappears when one of the spark plug wires is removed, then the noise is probably coming from that cylinderThe cause may be either the rod bearing, piston pin, or the piston, which has quieted down because the load has been removed from the cylinderIf rod bearing has failed, the noise will be loudest when the engine is deceleratingPiston pin noise and piston slap are generally louder when cold engine is first startedCarbon build up in the combustion chamber can cause interference with pistonMany times the source of an unusual sound may be isolated by using stethoscope or other listening deviceOne such device is long shank screwdriverAllow one hand to extend over the handle of the screwdriverThen, place the clenched fist against an ear, and make firm contact with the other end of the screwdriver on the engine block, at each cylinder or noise areaTake care and use good judgement when using this method of attempting to detect the cause of problem because the noise will travel through other metallic parts of the engine and could lead to false interpretation of what is being hear hearingLEAK DOWN PROCEDU