I just bought a 1980 Yamaha 25 sailboat the engine, a yanmar ysm8, needs a new exhaust system including a muffler. Both the mixing elbow and muffler are leaking. I found a source the engine parts, but can't locate a muffler that would work in the engine compartment. Most manufactured mufflers are top in and top out. The existing muffler is bottom out. Does anyone have a solution?