I have a 2006 Nitro 189 sport with a Mercury Optimax 115. Last summer, the fuel lines disintegrated and clogged up the engine. My mechanic replaced the fuel line, fuel pumps, spark plugs and for good measure, the water pump. Later, I was still having problems with the engine quitting and running roughly. We thought cleaning the injectors would clear that up. When the mechanic checked the cylinders, #1 piston showed a 50% reduction in hp. He says I should get another engine before this piston throws a rod. Also, rebuilding the engine can cost as much or more that getting a used engine. Is this right? Can I find a comparable used engine that will fit my boat? Does anybody know what engine I should look for?