I have a 1973 Mercury 110 9.8 hp. tiller. I was given this when I bought the boat. No Spark and a total mess. I rebuilt the lower end, carburetor, water pump and a new wiring harness; and it runs great. When I tried it on the water, it wouldn't go in reverse. On the bench it was ok. What happened between the bench and water? It has a steering connection on the transom mount that shows it may have been connected to the steering wheel at one time. Could that be the problem?