After a WOT run, I hear a faint knock/rattle when shutting down (backing off the throttle to stop the boat). Only on the "backdown" is when I hear this.<br /> Timing a tad high? OR???<br />97 Yamaha 150 V-max with lots of hydro-tech parts running super unleaded. 70-72 size jets, 175psi compression, Timing around 24 degrees.