I own a Jet Ski Shop in San Antonio, Texas. I've been working on Jet Ski's since 1985. One tip. When torquing down the head bolts be sure to torque them cold to spec then after starting the engine to warm it up, re-tighten the head bolts once more, while hot, to take up any slack created by heat expansion. This is especially relevant when working on the 440 or 550 motors since half of the head bolts screw into the engine case and stretch quite a bit when hot.