Exhaust Elbow Clogging Frequently

[Maine Sail]

Originally Posted by Chief Engineer

Two years is salt water is "it"

Interesting...? I know a ton of boats that go against that grain of two years in salt is "it".

Mine is currently 8 years old with 3000 hours. My last one was 22 years old with 1400 hours, all in salt water. The two boats I race on, one is 24 years old and the other is 23 years old, both have about 1700+/- hours on them, all in salt, and both have original exhaust elbows. The last Yanmar I owned went 19 years and 2100 hours.

[straycurrent]

I have a 3qm30 with a home made galv exhaust riser,sea water is injected after the elbows .this is 14 years old with no problems.We also run at about 1600-2000 rpm .Had to do a rebuild after 13 years(engine history unknown before that )one cylinder had broken rings but the other 2 were in very good condition.I`m not sure why deisels need to be run hard,I think ours has done pretty well being nursed a bit. We can run up to full revs if need be ,but its a lot more noise and fuel to go not much faster.

[Dreaming Yachtsman]

John,

I discovered a similar carbon buildup on the exhaust elbow on my Yanmar 3GM30 FC engines about a year ago. I posted to this forum at http://www.cruisersforum.com/forums/...ons-16273.html and found out that I had been running the engines too slow. They really do need a substantial load on them to keep the carbon build up in check.

[FloridaWriter]

Originally Posted by Maine Sail

Interesting...? I know a ton of boats that go against that grain of two years in salt is "it".

Mine is currently 8 years old with 3000 hours. My last one was 22 years old with 1400 hours, all in salt water. The two boats I race on, one is 24 years old and the other is 23 years old, both have about 1700+/- hours on them, all in salt, and both have original exhaust elbows. The last Yanmar I owned went 19 years and 2100 hours.

The Yanmar master distributor in St Pete says Yanmar recommends replacing the mixing elbow every 5 years.

[s/v Jedi]

You should only replace the elbow when you find it too far gone while inspecting it. If it's rotten half away after 2 years, it's insane to put it back for another 3 years and if it's still fine after 5 years there's no need to replace it other than helping the shop survive the difficult economy.

Flush the engine cooling circuit with fresh water now and then, especially when you're not going to use the engine for some time. Close the seacock, open the strainer and fill with fresh water from hose; start the engine while feeding water with the hose for 10 minutes or so.

cheers,
Nick.

[Steve W]

Would it make sense to try to shotblast the rust and carbon buildup out of the elbow? My company has a huge shot blast room as well as a hand-held system and would be willing to try one at no charge to see if it will work. Plant manager thinks it will only take a few minutes.

Steve W.

[olepedersen]

The best way to clean them is to remove the elbow ,take a strong propane torch,and heat it as much as you can, when hot hit it with a large hammer and all the scale falls off. let it cool and reinstall. I have done to 3 engines, not all yanmar it works , but i do carry a spare on my boat , it is still new in the box after 4 years , my engine is also a 3gm30. Ole

[s/v Jedi]

Steve,

If you have a new elbow as back-up, why not try that? I never found the need for it and just use a pipe-brush and screwdriver to clean them.

cheers,
Nick.

[Chief Engineer]

I have five exhaust elbows that I keep for show and tell. All rusted out, cracked, blown out......why go thru the trouble of trying to extend the life...when they usually crap out at precisely the wrong time.

I am not trying to sell exhaust elbows.......I replace them.......In the long run it costs about the same or less than removal, cleaning and reinstallation and you are assured of no CO leaks from a deteriorating exhaust sysytem