I've brought the tillers and the tiller bar home for repair. Over the winter a number of the epoxy joints failed where I used it to glue oak. This limits the problem to the tillers, motor mount and hast head and foot. All key areas but all repairable. The joints have failed only where I used glue as the sole method of fastening. No failures where glass cloth or mechanical fasteners were also used such as at the motor mount, both or on one side of the tillers, screws. You can see the second case in the close up photo. I've checked the motor mount and there are no problems there but I do know that the mast foot has a split in it. I'll fix this when I get a chance to take down the mast or crawl up it to inspect.
My plan for repairs is to reglue and add screws as possible. The tillers as the are of oak are pretty heavy so if the repair doesn't work I may consider remaking them of a lighter wood though not sure what that would be.