Mixing Elbow Removal / Replacement Help Please

[capn_mark]

Hi folks,
I have a 1986 Hunter 34, and I have been searching around in the archives about removing the mixing elbow, and it looks like it makes the most sense to remove the manifold with it and fix at home on the bench.
Unfortunately my boat is a 600 mile drive from my garage and biggest tool selection, so I wonder if someone could please tell me the things I may need? The elbow has not been replaced for many years (whoops...) and it has developed a tiny weep when cold, so I need to get this done.
Is there a link to a desription of the process that I might have missed?
Thanks for your help,
Mark

[svHyLyte]

Mark--

What engine do you have? In most cases, there usually are only two or three bolts holding a mixing elbow in place and, aside from having to worm your way into the space to reach them, it is not difficult to make a swap and definately does not require removing the exhaust manifold. On our old boat with a Yanmar, replacing the mixing elbow might have taken 45 minutes. On our current yacht, with a Perkins 4-108, it only takes slightly longer simply because access is more difficult and the Perkins nozzel comes in two parts--the elbow and an injection nozzel.

FWIW...

[daddle]

Might need to drain the coolant - this surprised me on a Universal M4-30.

[capn_mark]

Hi guys, sorry I forgot to say it's the yanmar 3gm30f
thanks,
Mark

[roverhi]

The 3GM30F exhaust is bolted to the engine. Believe it's two bolts and the riser pipe and elbow come free from the engine. That's the easy part. On my engine, working on the dock, could not get the elbow off the exhaust riser pipe. Had two large pipe wrenches but two of just couldn't get a stable enough purchase or the torque to unscrew it.

Finally called a Diesel Mechanic in frustration. He used a humongous winch in has truck to hold the riser/elbow, an even larger pripe wrench with about a 2' cheater bar on it, and a bit of heat from an acetaline torch to get the elbow off. Unless you are really lucky, you aren't going to get the elbow off with just pipe wrenches and definitely not in place on the engine.

Don't remember the size of the bolts on the riser flange probably a 17 or 19 metric socket. Take a normal metric socket set and you should be able to get the riser/elbow off the engine.

[svHyLyte]

See Good Old Boat: The sailing magazine for the rest of us= It might be wise to purchase a copy of the shop manual and parts catalog that will tell you what you need to know now and in future. Be careful about ordering Yanmar parts. If you get the wrong item, Yanmar only acvcepts returns within 15 days of the date of delivery.

FWIW...

[Tropic Cat]

Get your free copy of the Yanmar diesel here in PDF format

The mixing elbow is an easy maintenance item, which you either clean the carbon out of it or replace it. Not sure why you'd need your workbench.

[svHyLyte]

Originally Posted by Tropic Cat

Get your free copy of the Yanmar diesel here in PDF format

The mixing elbow is an easy maintenance item, which you either clean the carbon out of it or replace it. Not sure why you'd need your workbench.

Tropic--His mixing elbow has a pin-hole leak. Sounds like time for a replacement rather than cleaning, no?. According to Yanmar they are 500 hour replacement items.

FWIW...

[capn_mark]

MAny thanks everyone. We're off the boat tomorrow, hopefully sail for a few days, then pack her up for the winter and take the manifold and elbow home!
Thanks again,
Mark

[Chief Engineer]

Pack her up for the winter? It's October!!!!

[capn_mark]

Originally Posted by Chief Engineer

Pack her up for the winter? It's October!!!!

I'm in Western Canada, Chief! We'll charter somewhere south in feb, but we're just about done for this year. I'm in Calgary, the boat is on the west coast. It's actually 70 degrees here, so we'll get out a bit more, but it will be chilly very soon.