Yep, the groove in the shift shaft aligns with the hole in the connector/joiner. the bolt has to have perfect clearance or it won't thread into the far side of the connector. If the bolt threads strip out, you can use a tap/die to clean the connector threads and use another bolt. The impeller will right itself after you put the top cover of the pump down over it. The shaft is drilled for a little keeper pin that engages the impeller, the end of the round pin catches the impeller to key it to the shaft. make sure your water tube connects in both grommets, top and bottom, when you put the LU back on. it's easy to miss the bottom grommet the first few times. The carbs look complicated, but aren't. if you built model stuff as a kid, you can handle it. just work on a clean surface and take it apart logically. here