I have a 1996 90 hp ocean pro that is sluggish out of the hole and will only turn 3500 rpms. After about 45min to a hour of run time at a fast idle is shuts off as if you turned it off. Ive rebuilt carbs & fuel pump and changed all gaskets and still runs the same. Have good comp. & spark on all 4 cycl. Is it possible a coil could fail when it gets hot or am I looking in the wrong direction?