My Boat was in fresh water since 2003 and until 2years ago when purchased it and moved it in to the sea. I am trying to decide whether it is time to replace the mixing elbow on the yanmar 3gm30F (~300h)?
This is a maintenance issue and according to some, needs to be done every 2-3 years or every 400 engine h.
Was wondering if anyone here has done it and if there is any advantage in replacing the yanmar stock elbow with compatible ie SS aftermarket?
We replaced ours 2 years ago when it started to rust through & leak. Easy project install. Took the old one over to a local welder who welded it up and polished it out as a spare. Tried exhaustelbow.com, but he did not have my elbow.
I replaced my mixing elbow in December of 2014, but my Yanmar is a 4JH3-TE. I had over 3,000 hours on the engine at that time and there were no leaks or rust; but I did it as preventative maintenance issue. The original was still in fairly good condition and I saved it as a spare. I replaced the elbow with another Yanmar and the cost in US dollars was $540. Labor was about $50. I recently had the local boatyard replace my engine mounts and to do so, they had to remove the mixing elbow which remains in excellent condition. My engine now has 4,080 hours of use.
I also recently replaced my elbow on my 3GM30F with a standard Yanmar replacement elbow from our local supplier and from memory the price was around AUD300, but I could be wrong. The metal gasket was easy to remove, most came away when the elbow was taken off and the rest came off pretty easily with a a razor blade scraper. Frankly a much easier job than I had anticipated.
This is only the second elbow in 14 years of ownership so Im pretty happy with the sacrificial type of elbow (non SS), I had thought about getting a SS replacement but in the end did not and was happy because when I took off the elbow my biggest problem was the carbon buildup inside which a SS elbow would also suffer.
When I did this change I also took the opportunity to flush the raw water (in my case saltwater) circuit of the heat exchanger with a lime reducing agent to help remove growth buildup from the barnacles/coral after 10 years of use. Process took several hours with a spare bilge pump pumping the solution through the system from a bucket continuously but definitely helped improve water flow through the heat exchanger.
Thank you for your input and suggestions above. The past several days I got some quotes for OEM elbow replacements as well as contacted a couple of aftermarket suppliers including Ben at mixing elbows. com...
The available replacements I found where steel, welded SS and investment cast SS. Spoke to a friend of mine who is a metallurgical engineer and an avid sailor and decided to order the cast SS replacement. To make sure I have all the dimensions in order and regardless of the "replaces part number....etc" I decided to remove the existing mixing elbow today, measure and than order tonight the replacement.
It looks nice and clean outside but for piece of mind, need to see what corrosion did since 2003 on the inside.
This is after removing the sea water hose:
This is the exhaust line connecting the elbow to the Vetus muffler :
Well, surprise surprise!!! The mixing elbow is made of Dur-Aluminium, no steel or SS!! Here is how soot accumulated inside the coaxial configuration of the elbow:
As expected, soft soot deposit inside the elbow but the internal tube feeling solid and well attached to the exterior tube. No corrosion expected.
Here is a pic of the mixing elbow flange:
Again all good, no bad surprises.
Here is a pic of the engine section to which the elbow flange was attached:
The gasket that was sitting between the elbow flange and engine block was in good shape however I removed it since I purchased a new one already. The gasket is interesting, is two layered with grooves on one side, actually pretty amazing. Have never seen such thing before. Not something that can easily be matched by aftermarket providers.
Will have the elbow cleaned tomorrow and re-install it on the weekend.
I am glad I did not preempt and order the replacement part before examining the existing one (not characteristic of me to have such patience ). Dur -aluminium will last forever in marine environment in conjunction with a 3 cylinder banger. All good, no need to carry spares ...will include as part of maintenance cleaning the elbow every 2-3 years just for piece of mind and only if I don't bite the bullet and buy a Hanse 385 (my wet dream boat).
Last Edit: Mar 27, 2017 17:39:09 GMT by MalcolmP: photo link