Today I removed, inspected, and reinstalled my exhaust mixing elbow. As you know the engine manual says replace at 500 hours and they make two exhaust elbows. One at approx. $260. and one at approx. $900. Naturally, the C-387 has the larger, heavier, more expensive one, but it should last longer. I talked with a fellow sailor who attended the Yanmar engine school and the mechanic/instructor said to inspect at recommended interval and only replace when needed. I have 950 engine hrs. and my elbow looked good inside. No visible wearing away of the metal or carbon build up. The following is the procedure I recommend for removal:
- Remove raw water hose.
- Unbolt 4 nuts and remove elbow.
- Have someone hold exhaust hose (3 3/8 in. O.D.) while you twist elbow out.
The exhaust hose is large and only slightly flexible. I was unable to remove it from the elbow