Black Smoke Sluggish Performance

[Mike Pettee]

This isn’t a “what could it be” post. I just wanted to chronicle my last few days for anyone who may need reference         Back story. Christmas Eve sunset boat ride with my family and I noted the boat was sluggish on the port motor to come up to cruise. It would get there and WOT maintained it’s 3150 with no loss in speed once at cruise and above.  No puffy black smoke and I didn’t check the exhaust directly. I thought must be fuel filters. Swapped filters but still sluggish. This time I decide to directly check exhaust. Sure enough mixed in is dark smoke.          Thanks to the awesomeness of Tony’s articles and past experiences I immediately checked hoses and clamps. All good. No loose clamps no split hoses.    What do I notice? An air filter that had a loose clamp and wasn’t all the way on, leaving the turbo for God knows how long to intake unfiltered air.    Pull the filter off. Turbo looks funky, almost caked in salt so apparently this filter had been like this for a while. All on me as I should have noticed it. Get the turbo cleaned up best I can. Free spins fine no excessive noise or movement. This combined with the normal performance at cruise to WOT leaves me to feel the turbo is good. I’ll give it a good cleaning when the bots back together.            So to the aftercoolers. By now I’m realizing the air side of the cooler has to be a mess. The smoke, sluggish over the hump performance, and then finding the air filter….I’m expecting what’s coming. It’s time for normal maintenance anyway so since I’m down there I’m taking them both off. Pull them off.    Here are the starboard (clean) and port (smoke/sluggish/dirty) air sides.          I’ll update in a week or so when I get all these back on as to wether the smoke issue is resolved, but I’m pretty confident I found my culprit.             

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[Mike Pettee]

Just a follow up. 

I FINALLY got the air side back on. Needed to order a better set of snap ring pliers. Then still needed the right tool. In this case my wife. To crawl outboard of one of the motors to hold turbo housing in place. And then I did the opposite and she put on the clip ring. 

 

After that the rest was smooth. I swapped the top aftercooler bolt for a stud. 100x easier to install. Then buttoned everything up. No leaks I could see at the dock on the bad side. Could be I fixed when going through the clamps. Could be something that only shows itself underway. Will find out. Small leak to repair on the starboard side gear cooler drain but simple fix. 

 

The results. No more sluggish performance. Immediate response and up in plane. Small bit of black smoke over the hump but that’s always been that way. 

I also had some seats redone for both my boats while I was fighting this issue. 

https://photos.app.goo.gl/T9Y2i6oUrzFCUxBG7

[Rob Schepis]

I always tape them over or stuff a rug, etc.  Not sure on your exhaust design but make sure the wet exhaust is tied up high and secure…

[Mike Pettee]

No luck on the clip yet. 

Sidebar question. We had a death in the family and have to go north for a week. Currently the air side of the turbo is exposed and the tube to the intake manifold is open. Should I wrap them up? Or are they fine as they sit for a week?

[Rob Schepis]

For a first go at it why not clean the suspect area spic -n- span and then go for the sea trial and check it again when back at the dock for salty wetness.  Much safer that way.  Good to hear on the coolers.  As to the clip, the big pliers win and a second set of hands and a smear of grease too.

[Mike Pettee]

I do have dorade boxes- or a variation of such – built into the vents on the hull sides. I figured it was sucking in salt air/water from the salt and Tony confirmed. 

Its going back together on Saturday. I am not looking forward to the ride on the outboard side of the engine underway. But that is what it is going to take. I have an idea where it is coming from, but will not be sure till I take the ride. 

Coolers came apart and went back together smoothly. Cleaned up very well.  Replacing the turbo clip has proven my nemesis so far. 

[Rob Schepis]

She is a low profile hull.  Do you have dorade boxes internal to your engine room vents?  Lets see some pics of the ER vents, in and out.

[Tony Athens]

Feeding your turbo intake saltwater laden air

This is really simple—————-You have been feeding your engines turbo (an efficient and powerful  1-15 HP vacuum cleaner) that has been sucking what ever it can get  at up to 1500 CFM  at WOT of ( in this case) saltwater laden air…………………………………….Find the source ( you may have to go for a ride inside the engine room will all closed up in crappy weather) , but I’ll bet you’ll find the source doing it that way. Air vents on the side of the vessel just under the rub rails?  Some pics??                

[Mike Pettee]

Turbo

[Mike Pettee]

• See attached.

[Tony Athens]

Let me see the end  surfaces on the housing–both ends, especially the bottom————Clear & infocus

[Mike Pettee]

I’ll get to the turbo housing Tuesday morning. Here is the aftercooler off the side with the salt. 

[Tony Athens]

Regardlees of leaks, etc–Only ONE way the intake side of the turbo can look like that–SALT water being sucked into the intake/thru the aircleaner  from an external source. Get the aftercooler off, apart and on the bench………….. Get your turbo intake side off.. Take off the heater grid–More pics needed before you clean anything.   Tony

[Mike Pettee]

Salt. It was a wtf is that moment. So I wiped it and tasted it to be sure. Salt. Should say it wasn’t the fan but just the housing up to the fan.  I’m sure the fan for enough of it but just sent it on. I have pulled it apart and cleaned it up and it is fine. No play no noise and seemed to avoid any damage to fan blades or housing. It was also only on one side… That confuses me a bit. But that was the side of the filter that was off. See pic attached. Thinking maybe it just built up over time.  I have no water leaks back there. I had a leaking raw water pump but replaced it immediately. Could be a ventilation issue as this is the outboard side of the port engine. Other engine has no issues like this. That cooler is off for maintenance and the turbo cleaned up too.  Either way aftercoolers will be back together Tuesday and back in Wednesday morning. Hope to have results by Wednesday afternoon.       

[Rob Schepis]

Keep us posted. Caked in salt?  How’s the rest of the engine and engine room as a whole?  Maybe the ER ventilation can be approved upon to eliminate the salt?

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