When rebuilding the Sea Doo 657 shortblock, there is a thing called "squish gap" that has to be set. It involves assembling the shortblock, inserting a piece of solder in plug hole, turning engine and seeing how thick solder is. If not in tolerance, motor is disassembled and thinner/thicker base gasket is installed. If you don't do this and gap is wrong, serious engine damage occurs.
Tools needed:
Procedure:
