We were having intermittent shut down, inability to run the engine over about 2000 rpm without choking and much black smoke. The exhaust elbow was plugged from 16 years of short time running under light loads. Replacement has done a world of good.
On related note an owner reports: "On survey we discovered considerable wetness in the hull, starboard aft quarter emanating from the exhaust outlet. You might want to alert your members of the importance of maintaining the caulking around the exhaust tube where it exits the hull. I checked several other J-30's with a moisture meter and found, without exception, had similar problems. The degree of migration of the water in all cases was significant, often as far forward as the aft end of the keel."
