exhaust elbow

[BOBBIN]

I SEEM TO HAVE A PROBLEM WITH COOLING WATER NOT MIXING WITH EXHAUST GASES IN THE EXHAUST ELBOW. MY ENGINE A YANMAR 3HM35 RAW WATER COOLED ENGINE IS PUSHING OUT WHAT APPEARS TO BE STEAM FROM THE EXHAUST WHICH INCREASES WITH THE REVS.
HAVING CHECKED FOR BLOCKAGES AND THE ENGINE NOT OVERHEATING I AM BEGINNING TO THINK THAT THE EXHAUST ELBOW MAY BE BLOCKED WITH CARBON OR BE IN NEED OF REPLACEMENT.
HOW CAN I CLEAR THE CARBON IF WHEN TAKING IT OFF THIS APPEARS TO BE THE CAUSE?
ANY OTHER SUGGESTIONS AS TO THE SOLUTION TO MY PROBLEM WILL BE APPRECIATED.

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[Talbot]

Welcome to the forum. using capitals is the equivalent of shouting.
I assume the elbow is metal - if so a trick used on small motorbikes may well work, take the elbow home and get a bucket with a solution of caustic soda and place elbow into bucket overnight.

The caustic soda solution is dangerous and it is essential that you take adequate precautions, gogles, clothing, proper heavy rubber gloves, no children or animals etc. but should remove the carbon deposits.

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[mirabriani]

Bother! As a motorcyclist (biker) I could have answered that one (I should have heard it without logging on) Talbot has given a definitive answer. As an alternative you might prop it up with a blowlamp pointing into it, in well ventilated area. This should burn off the carbon.
Regards Briani

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[boatless]

As an ex motorcyclist... if you have an autocleaning electric oven - works a treat. Just do it when your wife's out.

<hr width=100% size=1>my opinion is complete rubbish, probably.

 

[LORDNELSON]

Last year my 3HM35 started blowing steam from the exhaust; I had forgotten to open the cooling water inlet skin fitting..............................just a thought!

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[Talbot]

no such thing as an ex motorcyclist - only one that temporarily is without his favourite form of transport! /forums/images/icons/smile.gif

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[Sunnyseeker]

Is that similar to tennis elbow?

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[boatless]

If you had seen me under the post office van you'd realize that I am definitely an ex biker!

<hr width=100% size=1>my opinion is complete rubbish, probably.

 

[AndrewB]

I'd be a little surprised if this is due to carbon build-up in the exhaust elbow. Blockages in the exhaust line tend to result in incomplete combustion and so smoke.

The more usual reason for steam is either (i) inadequate cooling water, as Lordnelson says or (ii) water getting into the combustion chamber. The latter may be condensation during startup, but if it persists suspect your filters, dodgy fuel, or a blown head-gasket.

Previous threads have mentioned distinguishing white smoke and steam in the exhaust, the causes of which are different, but I assume you are sure on this point.

 

[NigeCh]

More likely cooling water starvation

Seawater deposits a nasty calcium carbonate deposit in the impellor housing between the impellor blade deflector and the outlet pipe to the engine, gradually closing the outlet off .... Ergo, less cooling water to the cylinder heads = more steam.

It's only a 10 minute job on GM series engines to take the impellor housing off and check it for scale deposits. If there is scale then chip it off. If there is no scale then you know the problem lies further upstream.

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[NigeCh]

Al + NaOH = FIZZ !!!! (nm)

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[Birdseye]

Examine your elbow carefully. (cue facetious comments). It is possible for the elbow to corrode after a lot of use, and sea water starts to splash back into the engine. This in turn can corrode the head. I know - it happened to me.

When the engine is working hard, some steam is normal. Particulary on a cold damp morning



<hr width=100% size=1>this post is a personal opinion, and you should not base your actions on it.

 

[Birdseye]

Examine your elbow carefully. (cue facetious comments). It is possible for the elbow to corrode after a lot of use, and sea water starts to splash back into the engine. This in turn can corrode the head. I know - it happened to me.

When the engine is working hard, some steam is normal. Particulary on a cold damp morning



<hr width=100% size=1>this post is a personal opinion, and you should not base your actions on it.

 

[stephenmartin]

Hi Bobbin...

I had a similar problem three weeks ago....en-route to France an engine started to produce loads of smoke and low power....limped to France on one engine....all the French experts said it was Head Gasket, Water in the fuel, Air in the diesel....did everything they said....one week later a truck mechanic narrowed it down in 30 minutes to the Fuel Injection Pump timing that had slipped.....You should have seen the white smoke.....had the French cops and harbour master checking I was not on fire

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[PIGLETSDREAM]

Try the link attached. It is a Yanmar forum, lots of old sages and then someone from Yanmar posts the prper answer and if you are lucky a link to the Yanmar manual



http://yanmarhelp.com/msgboard.mv?parm_func=showpostform




Must go matron is comming

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[AndrewB]

Injection pump timing error results in white smoke, not steam. An expert wouldn't confuse them, and Bobbin seemed sure it was steam.

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[steve28]

I was just looking at your post, i dont doubt what your saying about the injection pump but im curios to know what engine you have and how it managed to slip ?


steve

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