Stainless Steel Yanmar Exhaust Elbow

[charles_reed]

An amusing, frequently ill-informed, sweeping series of statements about exhaust elbows.

My 3YM20 Yanmar was supplied new with a stainless exhaust manifold. Unlike the one specified by the OP it's in 316 stainless instead of 304.
The price reflects its far lower raw material cost, greater ease of working and welding. In fact it's such good value for money that I'm ordering one before I attempt cleaning my current mixer elbow. I don't expect it will last the 2500hrs that my current one has done, without cleaning.
My current elbow has a definite weld-leak, but unlike the Yanmar malleable iron cast alternator mounting is unlikely to fatigue fracture.

 

[rob2]

Many years ago now (significant as there have been no failures since) we adapted the cooler engine off a Thermoking truck for our boat. This is, in essence, a 2GM though the front housing is for a different set of ancillaries. Anyway, wanting a water injection elbow, we took the original mild steel exhaust stub to a metal worker, who bent two tubes and welded them to the mild flange - quick and dirty, but who's ever had a flange rot out? I believe most flanges actually conform to a standard and many can be bought off the shelf for very little. In fact stainless bends can also be bought off the shelf, so it may only be a question of getting stock items welded together.

Maybe not the perfect metallurgy, but yields a life expectancy in decades, not seasons.

Rob.

 

[Norman_E]

My bigger 4 cylinder Yanmar had a small leak of coolant that resulted in the engine mounting directly below the exhaust elbow getting a bit rusty. Due to the overheat alarm having come on when the engine was given a good "Italian tune up" I have had the cooling system stripped down which resulted in bits of an old impeller being found in the heat exchanger. When removed the flange of the elbow was found to be quite corroded. The man who does my engine work in Marmaris has made a new stainless elbow.

 

[NPMR]

I have a pet irritation regarding these elbows. I have a Yanmar engine and the manufacturer states that it should be inspected every 200 hours use or it might fail!

To buy the thing in the UK costs the same in "£'s"as the US pays in "$'s". Same part number, same unit. So about a third or more cheaper.

Yanmar claimed some kind of 'special' costs in the UK which I challenged, when I queried this but in the end they agreed to reduce the UK price, but I saw no evidence of this actually happening and the post seems to imply that the issue is still live. As the engine I have is a 25+years old design, and the problem of quickly rusting or problematic exhaust elbows has not changed, maybe Yanmar just like the profits.

If we don't moan loudly enough, they have no incentive to change. It's up to us. I did my bit. Who else will?