I had to replace both of mine a couple of years back. You are sharp if you noticed they are beginning to fail. Mine looked perfect on the outside but on the inside, a thin flap of rubber peeled off and cut off exhaust from exiting... Fortunately mine blew a hole in the side of the pipe, otherwise would not have realized the overheating that was going on (gauges failing at the time).
I was in a bit of a difficult situation and was the providing the family boat in Montana for a couple of families. No boat shops had the appropriate hoses in stock. Fortunately NAPA had brought in a custom piece of hose for a different application and it was perfect. I cut off 2 inches and cut the leftover piece in half to fit both sides perfectly. I checked it again last year... working perfectly and no signs of problems on the inside.
Two days later I saw a different breed of boat with smoke pouring out the back as it was going across the lake. I raced over to see what was up and believe he was experiencing the same problem. Hoses were smoking hot and melting. His boat was also about 10 years old. My advice? Pull your rubber exhaust hoses off on one end and have a look if you have not done it before. Could save you from being broke down on a warm day on the lake.
