Sheen/Sooting from my 7.6BTD - troubleshooting advice?

[GnrlPatton]

First off, I will say that I'm not sure it's even a problem - let me explain.

I was in a popular bay last weekend along with dozens (hundreds?) of boats, and my yacht club was doing it's annual raft up so we had 2 strings of 15 boats stern to stern. It was a hot weekend, and my wife wasn't feeling well, so I ran the generator a lot to keep the cabin cool for her. Others around me, as well as in the whole bay, were also running generators quite a bit through the weekend.

On Sunday when I started packing up to leave, I pulled the dinghy out of the water and noticed that there was a black ring around it right at the waterline. It was tied up behind my boat except for the 30-60 minutes we used it to dinghy around the bay and see friends. At first I thought it was from other boats (we had seen a sheen come through our anchor lines earlier in the weekend, we assumed from boats ahead of us in the bay, but definitely not from any of us the way it was flowing), but then I noticed it was mostly on the starboard side of the dinghy, which aligns with my generator exhaust port. We had dozens of people swimming in the lake, including behind my boat, and nobody came away with black face from it, only my dinghy.

I went yesterday to do an oil change on it, and just check things out, and the oil level looked normal and I saw no obvious signs of problems. There's no sooting around the exhaust port or leaks in the ER around the generator, and when running I don't see any obvious sheen in the water. I'm going out this weekend for Seafair for 4 days, and I'm sure I'll be running the generator a bit over that 4 days.

What would any of you do to check things on it to make sure she's healthy? Just watch for sheen or exhaust sooting? Again, I'm not sure if there's even a problem, but the amount of oily mess on the dinghy was a bit troubling to me, and I am suspecting there's something up with my generator, just not sure how to start troubleshooting on it.

Sorry for the long post, but wanted to get the entire scenario out there for advice.

 

[ttmott]

Did you pull an oil test sample before the oil change?

 

[GnrlPatton]

I didn't have the sample kit, but I do still have the oil in a clean bucket that I could probably sample and send in as soon as I get one. I usually always do the sample when changing oil, but I didn't have the time to get to CAT for an SOS kit this time, and I wanted to get the oil change done since it's been just over 100 hours since the last one.

 

[The Bill Collector]

My 8.0 BTD was smoking a little last season and leaving a little soot on the side of the boat, after 15 years with her I knew something was off. I called Kraken diesel, the tech asked a few questions and then removed the exhaust mixing elbow, it was over 50% clogged. He went on another boat and I ran to Gallery Marine to get the part. By the time I was back he was ready to walk off the other boat. The part was installed and no further issues.

 

[GnrlPatton]

My 8.0 BTD was smoking a little last season and leaving a little soot on the side of the boat, after 15 years with her I knew something was off. I called Kraken diesel, the tech asked a few questions and then removed the exhaust mixing elbow, it was over 50% clogged. He went on another boat and I ran to Gallery Marine to get the part. By the time I was back he was ready to walk off the other boat. The part was installed and no further issues.

Good info, thanks Mark. My first thought was I should call up Kraken and see what they thought, I may just do that. The exhaust elbow is pretty accessible for me, I suppose I could take it off and see if it's clogged before bringing him up to me from Tacoma (I'm on Lk Washington). Is there a cleaning procedure that can be done, or just best to replace if it's that clogged up?

 

[The Bill Collector]

Good info, thanks Mark. My first thought was I should call up Kraken and see what they thought, I may just do that. The exhaust elbow is pretty accessible for me, I suppose I could take it off and see if it's clogged before bringing him up to me from Tacoma (I'm on Lk Washington). Is there a cleaning procedure that can be done, or just best to replace if it's that clogged up?

Yes, you can take it to a radiator shop for hot tanking. I think you'll still need a gasket from Gallery. BTW Federal Way Radiator is now FW Muffler and they do not hot tank anymore. I thought I'd try at home with my old one with Muriatic acid and I think I let soak a little too long... It's kind of pitted now. :-(

 

[Strecker25]

We’ve got a similar thing with our 7.6. It hunts about 10v with no load, smooths out once a load is put on

Ours suffers from 150 hours of use since new, so it probably needs a full tuneup. The procedure for adjusting the timing and valve clearances is in the manual and seems straightforward but I think I might just have our mechanic come down and look at it. I wouldn’t be surprised if we need to pull the injectors for a cleaning too since they mostly sat their whole life.

I’ve put 20 hours on it this year and it runs ok, but blows a black cloud when it starts up and spots the transom up nasty. It also smokes a little bit while running

 

[The Bill Collector]

Our tech told me when you run, run it with a load or just leave it off

 

[GnrlPatton]

Thanks guys for the replies so far. I'm not even sure it was mine sooting up the dinghy, and I don't have any sooting on the boat, hunting, or any other problems. I'll definitely watch it this weekend to see if I notice anything else with it.

 

[dtfeld]

I get the same black sooty mess every once in a while. Mine runs like a top, right on speed, 120V right at 60-61 Hz load depending. I think it comes from the start up or shut down process where fuel injected but not completely burned. But I dont really know.

 

[LMBoat]

You might try putting a heavy load on it (close to the rated max amps, turn everything on then maybe a hair dryer, etc.) for a few minutes. I do this a few times a year. I get some smoke for a few minutes, then clears up.

 

[dtfeld]

If I'm running it, I try to load it up, I have 3 AC units so run all three plus water heater usually get the job done, but again I notice it right at start and stop.

 

[Skybolt]

I run mine all of the time and get that same sooty mess as well, sometimes worse then others. That said mine runs like a top, I have it set for 240v but each line is 120/60-59.5hz. Never a issue. I wouldn't worry too much about it. But I also have Detroit(s) as well, so I am use to that a bit.

 

[Strecker25]

If I'm running it, I try to load it up, I have 3 AC units so run all three plus water heater usually get the job done, but again I notice it right at start and stop.

3 ACs? Do you have cockpit air?

 

[Carver370]

My 8.0 BTD was smoking a little last season and leaving a little soot on the side of the boat, after 15 years with her I knew something was off. I called Kraken diesel, the tech asked a few questions and then removed the exhaust mixing elbow, it was over 50% clogged. He went on another boat and I ran to Gallery Marine to get the part. By the time I was back he was ready to walk off the other boat. The part was installed and no further issues.

I think you're on to something here. Mine does the same thing but runs perfectly. I will look into this, thank you!

 

[dtfeld]

3 ACs? Do you have cockpit air?

Yes. The original owner had large AC (16 or 18 KBtu) unit installed in the most forward cabinet on the port side behind where the cabin door swings shut. Works well, but I dont think the ideal location, I have to have the door closed to get air out of the main duct. I'll post some pics up...

 

[fwebster]

My 8.0BTD clogged up the exhaust elbow about every 800 hours. I just helped the new owner change it the second time at 1600 hours.

In GNRLPatton's case, it sounds like the generator may not have had a full load which will cause black smoke and excess sooting. The exhaust elbow is an easy part to remove and replace. It is so easy to remove/replace that having it cleaned doesn't make a lot of sense. So, go for it!

 

[GnrlPatton]

My 8.0BTD clogged up the exhaust elbow about every 800 hours. I just helped the new owner change it the second time at 1600 hours.

In GNRLPatton's case, it sounds like the generator may not have had a full load which will cause black smoke and excess sooting. The exhaust elbow is an easy part to remove and replace. It is so easy to remove/replace that having it cleaned doesn't make a lot of sense. So, go for it!

I had the AC going the whole time it was running, so it had a constant 10+ amps, with spikes up to 20amp when we had other things running. I think it's likely the exhaust elbow, so I'll start with that if I get more of the sooting this weekend.

 

[The Bill Collector]

I had the AC going the whole time it was running, so it had a constant 10+ amps, with spikes up to 20amp when we had other things running. I think it's likely the exhaust elbow, so I'll start with that if I get more of the sooting this weekend.

It's really a cheap part too... Around $100.

 

[dtfeld]

My 8.0BTD clogged up the exhaust elbow about every 800 hours. I just helped the new owner change it the second time at 1600 hours.

In GNRLPatton's case, it sounds like the generator may not have had a full load which will cause black smoke and excess sooting. The exhaust elbow is an easy part to remove and replace. It is so easy to remove/replace that having it cleaned doesn't make a lot of sense. So, go for it!

Its easy to get off, however one word of caution. Make sure you have a new gasket on hand, they are about $5. I just pulled mine for the first time, and found that over the years the exhaust manifold sealing face was pitted, requiring not only a new gasket, but a small bead of RTV to get it to seal completely. Unfortunately, the manifold isn't so inexpensive...I think I saw $800, so I'm intending to rework that this winter.

You can see what I'm talking about.

http://clubsearay.com/index.php?threads/westerbeke-7-6-btd-random-shut-downs.109847/page-2