I dropped the lower unit to replace the impeller and screwed up the shift rod lever, piece that connects the rod to the engine/cables. I thought I got a replacement but that doesn't seem to fit right. The old part is 318556 and the new one is 326644. THe new one fits on the shaft fine but seems to big and when on you can't shift anymore. Does anyone have any ideas? Or where to get old parts. It's a 77 evinrude 55hp.