We are a marine surveying business settled in Saint Martin, French West Indies, since 2005.

Low quality stainless steel used on Yanmar 3YM engines

Low quality stainless steel used on Yanmar 3YM engines

The above picture is a leak of raw water spotted at the exhaust elbow of the port engine of a Leopard 39, 2012. Engine had 500 hours:

Same problem was spotted on the starboard side (engine had 800 hours on this one). 

This is the culprit:

leaking exhaust elbow

Once cleant Up, you can clearly see a crack at the junction between the plate and the hosing:

cracked mixing elbow

We managed to weld back the port one:

The starboard one was totally rotten, stainless was cracked internally up to 1 cm within the tubing, so a new elbow was fitted (these elbows are sold for roughly US$180).

Can this issue be considered normal wear and tear, or do you think Yanmar uses cheap stainless steel ? We understand exhaust fumes and waters are corrosive, should 500 hours be considered normal span life of a stainless steel part ?