2000 Yanmar 3GM30F Black Smoke and no power
- Thread starter sailcapt340
- Start date
You might try some vibration, too, like tapping on the bolt heads after the PB Blaster has penetrated. That said, for something like this it's best to just be prepared for a broken bolt or stud, or a stripped threaded hole.
What is that loop you removed ?
Was the soot was on the inside?
It looks like a water hose...ahead of where the exhaust gas enters the exhaust? How would soot get in there?
My 2GM20F exhibits the same black soot in the exhaust water when I push the RPMs over 3000.
A very noticeable black stream behind the boat. If I run it that hard, eventually she will overheat.
But I don’t lose power.
Really curious what you find. I have never removed my mixing elbow (1988 O’Day 322) but I have only owned her for 5 years. Not sure if the PO ever changed it. I am on fresh water, and I keep hoping that means less carbon buildup in the elbow.
Greg
I'll try to get all questions here
SG,
I like the idea of bronze. And as of right now I have an email out to Mack Boring. Still waiting to hear from them.
Jvis,
Good advice, I'll take it and try. The area is really free of any rust that I can see. Hopefully this is a good sign. Tomorrow will tell.
Tally Ho,
It's a vented loop that was originally installed.The end you see comes from the top of the elbow the other end attaches behind the engine antifreeze head. I'll take a better picture tomorrow when I remove the elbow. The soot was in the first 1/2 inch of the hose and really just a dusting. The soot is in my opinion, blow back from the elbow, because it has nowhere else to go if the elbow is clogged.
Which, I hope is the case instead of the other scenarios and possibilities.
SG,
I like the idea of bronze. And as of right now I have an email out to Mack Boring. Still waiting to hear from them.
Jvis,
Good advice, I'll take it and try. The area is really free of any rust that I can see. Hopefully this is a good sign. Tomorrow will tell.
Tally Ho,
It's a vented loop that was originally installed.The end you see comes from the top of the elbow the other end attaches behind the engine antifreeze head. I'll take a better picture tomorrow when I remove the elbow. The soot was in the first 1/2 inch of the hose and really just a dusting. The soot is in my opinion, blow back from the elbow, because it has nowhere else to go if the elbow is clogged.
Which, I hope is the case instead of the other scenarios and possibilities.
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The elbow is off.
A slight tap on each bolt, a few drops of PB as I went, and they all backed right out.
What I found was a whole other story. Quite a bit of carbon buildup. A lot of carbon build up!
I'm still trying to free it from the Exhaust Hose and as that is just causing to much work in a small area I'm going to replace the 4 feet or so of Wet Exhaust Hose while I'm at it.
I didn't see any sign of gasket sealant when I took it off. Is there suppose to be?
Can't do anything else, as it's Saturday, and no one carries this whole unit in stock. With any luck, Monday and a few days for shipping or I may just go and pick it up if possible.
I'll post photos later next week of a completed job.
What a Big lesson I learned here!!
Thank you to everyone for the help and support. I Hope and plan, I can return it sometime but under better circumstances than me, for all of you.
John
A slight tap on each bolt, a few drops of PB as I went, and they all backed right out.
What I found was a whole other story. Quite a bit of carbon buildup. A lot of carbon build up!
I'm still trying to free it from the Exhaust Hose and as that is just causing to much work in a small area I'm going to replace the 4 feet or so of Wet Exhaust Hose while I'm at it.
I didn't see any sign of gasket sealant when I took it off. Is there suppose to be?
Can't do anything else, as it's Saturday, and no one carries this whole unit in stock. With any luck, Monday and a few days for shipping or I may just go and pick it up if possible.
I'll post photos later next week of a completed job.
What a Big lesson I learned here!!
Thank you to everyone for the help and support. I Hope and plan, I can return it sometime but under better circumstances than me, for all of you.
John
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I think that is the manifold that you have removed from the engine. Which is great it’s how I work on my mixing elbow. But the actual elbow threads into the manifold. I had a devil of a time getting the elbow unthreaded from the manifold. I had to get a large pipe wrench. If I am seeing what I think I am seeing, If you want to replace that entire thing you are looking at two different parts. The manifold and the elbow.
HMT2,
Yes you are seeing the entire unit, manifold, nipple and elbow. I looked at this from the very beginning and said there was no way I could muscle that elbow off without shaking and banging the boat off the mooring. And possibly causing more damage elsewhere.
So I opted for the four attaching bolts and tackle the whole thing on my bench.
Now seeing the carbon.... the whole thing is going away.
I've seen pricing at around $220 -270. I believe that's for a stainless steel setup (all three parts), but being Saturday I have to wait to speak with someone next week.
I did get a part number, which hopefully it doesn't change over the weekend, they come and go quickly around here.
It's 128990-13520
Yes you are seeing the entire unit, manifold, nipple and elbow. I looked at this from the very beginning and said there was no way I could muscle that elbow off without shaking and banging the boat off the mooring. And possibly causing more damage elsewhere.
So I opted for the four attaching bolts and tackle the whole thing on my bench.
Now seeing the carbon.... the whole thing is going away.
I've seen pricing at around $220 -270. I believe that's for a stainless steel setup (all three parts), but being Saturday I have to wait to speak with someone next week.
I did get a part number, which hopefully it doesn't change over the weekend, they come and go quickly around here.
It's 128990-13520
I'm sure you've seen it somewhere but just to be clear the manifold and elbow have left and right threads. So depending on which on part you're trying to loosen you maybe tightening it.
I have had a similar problem and that was caused by to little air for the engine. The air intake was clogged by the ventilation hose.
Don,
Yes, I did know the reverse thread coupling. But thank you for the heads up, with all that's going on sometimes you just get tunnel vision and forget.
But this part is destined for the hacksaw to cut it in half so I can see what 18 years looks like in there.
Patrik,
Yes they are all signs of something, unfortunately for me it was long over due. But at least it happened in port and not out sailing.
Yes, I did know the reverse thread coupling. But thank you for the heads up, with all that's going on sometimes you just get tunnel vision and forget.
But this part is destined for the hacksaw to cut it in half so I can see what 18 years looks like in there.
Patrik,
Yes they are all signs of something, unfortunately for me it was long over due. But at least it happened in port and not out sailing.
Well it's possible. Could always be a spare. I'll know better after it's off, cleaned and assessed.
For some reason that particular cast elbow really likes to carbon up. They sell them cheap enough that most people just pull them off and toss em’. I read somewhere to check the elbow for carbon at 250 hours. I have a different elbow (less bend, welded stainless) and it had a light dust of carbon at 300 hours. The Yanmar guys told me not to long idle the engine, or operate at low RPM. I’ve always wondered whether it would make a difference if you gave those elbows the race engine treatment - port and polish the passage for better gas flow.
Gunni!
Your right, it really is just the nature of cast metal. To many rough edges for stuff to cling to and then pile up, even if it feels smooth it really isn't. I'm sure the low idle at mooring for the "batteries" is a major culprit for the condition. But that's another series of conversations.
Greg,
Thirty? 30...wow! I have to say in the 18 years with this boat, I can only remember 1(one) time that I ever heard anyone even mention a Mixing Elbow. And that was in June of 2000 when the man who moored his boat behind me (we moor between two poles each in Wickford in a line up the harbor) said he had to change his Mixing Elbow.
Being that my boat was brand new, I never gave it a thought. Which leads me to today.
I wish just once, at a dinner, lunch, work, party, at the marina...anywhere, someone would have said those words. Maybe all this would be for nothing.
Hopefully others are reading this and thinking.
Your right, it really is just the nature of cast metal. To many rough edges for stuff to cling to and then pile up, even if it feels smooth it really isn't. I'm sure the low idle at mooring for the "batteries" is a major culprit for the condition. But that's another series of conversations.
Greg,
Thirty? 30...wow! I have to say in the 18 years with this boat, I can only remember 1(one) time that I ever heard anyone even mention a Mixing Elbow. And that was in June of 2000 when the man who moored his boat behind me (we moor between two poles each in Wickford in a line up the harbor) said he had to change his Mixing Elbow.
Being that my boat was brand new, I never gave it a thought. Which leads me to today.
I wish just once, at a dinner, lunch, work, party, at the marina...anywhere, someone would have said those words. Maybe all this would be for nothing.
Hopefully others are reading this and thinking.
You could run the engine for a short while with the water pipe in a bucket to catch the cooling water, just long enough to establish that you are not chasing the wrong problem.
Black smoke is over-fueling due to blocked intake or exhaust. Make sure the foam has not been pulled out of the air filter & into the intake manifold. The sudden onset of this problem suggests to me it's not the exhaust elbow, but cleaning it or changing it now is still a good policy.
Now the manifold is off you can use lots of heat (cherry red) to unscrew the nipple. However, I would replace both elbow & nipple with stainless.
Have you checked the engine rotates freely? Engage the valve lifters on all three cylinders & spin it over on the starter (if you don't have a cranking handle)....just a thought on a partly siezed bearing on water pump or alternator bogging the engine down.
Neil
Black smoke is over-fueling due to blocked intake or exhaust. Make sure the foam has not been pulled out of the air filter & into the intake manifold. The sudden onset of this problem suggests to me it's not the exhaust elbow, but cleaning it or changing it now is still a good policy.
Now the manifold is off you can use lots of heat (cherry red) to unscrew the nipple. However, I would replace both elbow & nipple with stainless.
Have you checked the engine rotates freely? Engage the valve lifters on all three cylinders & spin it over on the starter (if you don't have a cranking handle)....just a thought on a partly siezed bearing on water pump or alternator bogging the engine down.
Neil
That is certainly one cause of black smoke, falling into the "insufficient air" category. There are other reasons, including excessive fuel, which can be caused by issues that have a sudden onset, like a bad injector, bad injector pump, or even poor fuel.
I tend to think an injector went south. This is not bad to check, assuming you have the correct wrenches (might need nipple wrenches) and replacement squish washers, and the guts! You can pull injectors one at a time and run the engine, observing the spray pattern. Don't let the fuel spray hit your skin.
