I am having a few problems. I had my lower unit rebuit after it was destroyed last season. During the breakdown it was discovered that it was not the orginal lower unit. It had been replaced with an 85 hp housing which is supposedly the same as the 125. After researching the original gear ratio the gears were also wrong. My unit called for a 1.73:1 ratio. It was replaced to that ratio. That unit too blew up after 1/4 season. During that incident the drive shaft wiped the splines off the pinyon gear. Gear was ok, shaft was replaced. Now this is my second rebuild that I had done. Once I get over 24-2500 RPMS, It sounds as if I hit something (cavitation), although not all the time....there is a 5-6 second delay between hits, (all 3 motor mounts OK). The prop worked before but I figured that was the problem and replaced it with a new one. Still the same problem. Compression is great on all cylinders. As per my mechanic so is the spark. (Had a new stator installed last season). Any suggestions, (spark problem high speed or lower unit screwed?)
