Abstract: Worn screw threads in the lower unit of a motorboat are repaired by cutting off the trailing end of a housing that is formed integral with the lower unit. The cut off part has the worn screw threads formed in it. A replacement part having pre-formed screw threads is welded into place to replace the cut off part, and a screw thread-cutting tool is used to clean and remove warpage from the screw threads in the replacement part after the welding is completed. An alignment tool holds the replacement part during the welding procedure.

Abstract: Tools having utility in the repair of outboard units. A first tool pulls a propeller off its shaft, and a second tool pulls a bearing carrier off the shaft and removes it from the inside of the outboard unit. Both tools include an elongate screw that axially advances to affect the desired pulling and both tools engage radially disposed struts of the item to be pulled when operatively deployed. The housing of each tool includes puller members terminating in strut-engaging mating surfaces at the distal free end thereof that abuttingly engage the struts from behind and exert a pulling force against them as the screw is rotated.