Sorry brain fart impeller lets the water flow out of the spout right ? and the prop bush allows the prop to spin on either gear ? No had an old outboard that the bush broke while out fishing was a long row home lol the guy servicing thought it was the trigger or the cdi box, tested the trigger it wasn't responding correctly so it was replaced and made no difference ! I think he's a bit baffled ! I've now taken it to a local Mercury repairer but even they thought it sounded confusing but they'll be looking at it on Wednesday