Re: 5 hp Viking/seized and then…

[Don]

Brian-
Don’t take that gearcase apart until you have ruled out other stuff…You have to remove the powerhead in order to get the gearcase off, then rip the gearcase apart to inspect it…Drain the gear lube first, signs of water or burnt lube might be a better indicator of the bad shock problem everyone is referring to. I would hate to see you rip the thing to pieces and not find a problem. On the other hand, the water pump impeller should probably be changed on this old engine to avoid trouble. Once the gearcase is off for impeller replacement, it isn’t much more work to inspect the driveshaft shock assembly. Oftentimes, you can see damage to the upper seal/bushing housing when the driveshaft stretches out, after you remove the SS impeller plate.
Again, are you sure the engine did not seize due to an overheat? What gas/oil mix are you using? Have you checked the compression? Post some pictures of your engine if you can….
OK, just reread your post. You have already replaced the impeller and had the gearcase off….Unfortunately, this is not guarantee the engine is not overheating. Was the gear lube in good shape when you changed it?