Exhaust elbow riser needed?

[kbanman]

I'd like to replace the exhaust elbow in my Hunter 320 (yanmar 2GM20F) with a stainless one, but the one I got from exhaustelbow.com is decidedly a different shape from the existing one. The current one has a riser immediately after the engine, then injects the water. The new one comes out and down at ~45 degrees and injects the water much sooner.

Is there a reason I would want to mimic the riser, or can I just swap the new one in?

(Photos attached)

 

[Rich Stidger]

If you look inside the new riser, you might find that the water runs through a passage and is injected lower than the photo may suggest.
Is this an approved part from Yanmar? What does Yanmar say about this part?

 

[Ralph Johnstone]

Sorry, but everything in there is wrong from the word "GO".

The old mixing elbow on your engine is not the original elbow that came with the engine :

This is the real Yanmar mixing elbow in cast iron. It is cool to the touch when the engine is running WOT.

Exhaustelbow.com ................................ does not appear to be able to offer a copy of a C.I. Yanmar mixing elbow.

The recognized supplier of SS Yanmar exhaust elbow COPIES is HDI Marine at Stainless Steel Exhaust - HDI Marine

They will supply an identical copy of a Yanmar 2GM in cast 316 SS. They were about 1/2 the cost of purchasing a cast iron elbow from Stem to Stern five years ago.

 

[Tally Ho]

Ralph is spot on….the original 2GM20F is the one he pictured. It appears a PO came up with something different, and the one you bought is not the correct one.

Ralph’s link to a source is where aI would go to order the right part.

And the reason you want to use the tall riser is because you can get water backed up into the exhaust, which can lead to hydro lock and pretty much destroy the engine.

Greg

 

[Ralph Johnstone]

And the reason you want to use the tall riser is because you can get water backed up into the exhaust, which can lead to hydro lock and pretty much destroy the engine.

Picky. picky, picky .

I noticed that and then forgot to mention it. I was in the process of breaking up a fight between a parrot and a rabbit over an old, dried piece of apple while writing. They each had their own piece of fresh apple but wanted this prize.

I wouldn't have one of their devices on the back end of my Yanmar for two seconds "while the engine was off." There "may" be some baffling inside those mufflers but I wouldn't bet on it.

 

[Calif. Ted]

Yanmar refers to it as an "optional" part, called the "L" type, as opposed to the "U" type we are more familiar with. I've only seen the "L" type supplied as OEM with 3YM30 engines but the 3ym, 3gm30, and 2gm 20 all use same exhaust elbows. Whether safe to use in your application is unknown to me. I've always felt more secure in using the "U" elbow, currently have one from HDI put on a year ago. Perkins engines I've owned have used a similar exhaust to the "L" without problems.
Just found this page from Yanmar that shows both elbows on a 3ym30.
3YM30AE - YANMAR Marine International