The maintenance of Yanmar diesel engine mixing elbows is a continuing topic. This is a situation I ran into that I haven't seen discussed before. The engine raw water pump discharge hose popped off the pump while running at 2700 rpm. No damage to anything, and I was able to put the hose back on and come home at a slower speed. At no time did the engine overheat.
After a search of Yanmar forums and some thought, I decided that the mixing elbow was clogged enough to force the pump pressure to get high enough to pop the hose off of the pump.
I ordered all new parts from Torresen Marine. I did not want to try to mess with getting the exhaust elbow, joint coupling, mixing elbow apart so I just bought all new parts. Total cost (including new water hose) $420.
I inspected the parts after removal and found the small barbed elbow on the mixing elbow had narrowed from 1/2" to 1/8" with mineral deposits. So I feel pretty sure that the high pressure from this clog did cause the hose to pop off.
I will be putting the inspection of this small fitting on a regular schedule from now on. This won't keep the large mixing elbow from slowly clogging but may slow down the process. If you have a Yanmar and run it in salt or brackish water, do yourself a favor and give this item some love before it overheats your engine or pops a hose and fills your bilge.
After a search of Yanmar forums and some thought, I decided that the mixing elbow was clogged enough to force the pump pressure to get high enough to pop the hose off of the pump.
I ordered all new parts from Torresen Marine. I did not want to try to mess with getting the exhaust elbow, joint coupling, mixing elbow apart so I just bought all new parts. Total cost (including new water hose) $420.
I inspected the parts after removal and found the small barbed elbow on the mixing elbow had narrowed from 1/2" to 1/8" with mineral deposits. So I feel pretty sure that the high pressure from this clog did cause the hose to pop off.
I will be putting the inspection of this small fitting on a regular schedule from now on. This won't keep the large mixing elbow from slowly clogging but may slow down the process. If you have a Yanmar and run it in salt or brackish water, do yourself a favor and give this item some love before it overheats your engine or pops a hose and fills your bilge.