Yanmar Exh Mix Elbow Hose Barb?

[Bud22569]

During haul-out this winter I am going through the plumbing systems on my boat.

I am replacing my Yanmar exhaust mixing elbow. I found that the previous owner had installed a piece of carbon steel pipe for the hose barb on the mixing elbow. I am planning to use a marine bronze hose barb for this job on my new mixing elbow. Is the bronze hose barb the correct way to make the connection from the mixing elbow to the exhaust hose?

Thanks for any help.

 

[BobM]

I don't know if bronze can hack the chemistry going on in the exhaust. I'd probably stick with steel.

 

[SeaRanch]

Suggestion... If the "hose barb" is a "right angle" replace it with a "straight" fitting.

On my H31 Yanmar 2GM the hose barb went into the mixing elbow at a right angle. The right angle slowed down the water which caused the carbon build up faster. After replacing it with a straight fitting (had to move the anti-syphion to the other side of the motor box) listening to the water coming out of the exhaust, the flow was much better, for the next 2 years, no carbon build up sufficent to reduce cooling.

Bill

 

[Steve Dion]

Mixing elbow on my H'31 2GM had the "barbed" piece as part of the elbow.

http://hunter.sailboatowners.com/in...7&cat_id=25&aid=6707&page=article&mn=31_83-87

 

[Bud22569]

The hose barb I am asking about is the connection from the mixing elbow to the exhaust hose.

My mixing elbow outlet is threaded with 1.25" NPT pipe thread. The original mixing elbow had a section of 1.25" galvinized carbon steel pipe threaded into the mixing elbow outlet. The exhaust hose fit over and was clamped to the 1.25" pipe.

I guess my question is how to connect the exhaust hose correctly to the mixing elbow. Do I use galvinzied pipe, bronze hoze barb, brass hose barb, is there a Yanmar part for this function, or is there some other method for this connection?

 

[Don Crowther]

Mine's just galvinzied pipe with no barb. The hose just slides over and is held in place with a clamp. Not much pressure there just exshaust.
Hope that helps.
I've got mine off because I'm dealing with a heat exchanger problem.
Don

 

[Bud22569]

Mixing elbow on my H'31 2GM had the "barbed" piece as part of the elbow.

http://hunter.sailboatowners.com/in...7&cat_id=25&aid=6707&page=article&mn=31_83-87

I see that you exhaust hose fits over the outlet of the mixing elbow. My hose is not large enough to fit over the mxing elbow. My engine is a small YSM12R.

 

[Ron McCoy]

FondaFive. If your exhaust hose is too large to fit on the outlet of the mixiing elbow exhaust, then you've got too big of hose. I'm assuming you have the correct size mixing elbow on your engine. Someone in the past either put on a larger hose or changed out the elbow with the wrong size. The exhaust hose and elbow should have the corresponding diameters to fit properly. I'd double check both, as either problem can lead to overheating.

 

[Jalepeno]

Here is how my YSM-12 exhaust is setup on my CAL 2-25.

 

[Bud22569]

FondaFive. If your exhaust hose is too large to fit on the outlet of the mixiing elbow exhaust, then you've got too big of hose. I'm assuming you have the correct size mixing elbow on your engine. Someone in the past either put on a larger hose or changed out the elbow with the wrong size. The exhaust hose and elbow should have the corresponding diameters to fit properly. I'd double check both, as either problem can lead to overheating.

It looks like I have a bigger problem than I thought. I just looked in the Yanmar manual and it calls for a 50mm id (almost 2") exhaust hose fitted over the outside of the mixing elbow. Right now the whole exhaust system, including the trough-hull is sized for 1.50" hose. I guess I need to look closer at the exhaust system to see what it will take to bring it all up to the 50mm id that Yanmar calls for. I wonder why the inside of the mixing elbow outlet is threaded? The boat is 30 years old and appears to have had the exhaust setup in the 1.50" id exhaust for many years.

 

[Bud22569]

Here is how my YSM-12 exhaust is setup on my CAL 2-25.

Jalepeno, you exhaust mixing elbow setup looks very similiar to mine. It appears that you have some sort of pipe or hose barb threaded into the mixing elbow similiar to how mine has been setup. Do you know the size of the exhaust hose connected to the mixing elbow? Do you know what has been used as a hose barb on the outlet of the mixing elbow?

Perhaps decided way back when that they did not need to use the 50mm hose that Yanmar calls for. I am at a loss.