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'06 with monsoon, black soot/carbon


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Fired up the Bu this weekend and made a HUGE mess of black carbon floating around behind me. It ran just a touch rough and then settled down. I've noticed the back of my white bu gets very dirty/sooty throughout the year and just thought it was the 90 exhaust turn downs, now I'm not so sure. I talked to the dealer and the first questions was what octane gas I run. I said 89 but really it's 87 as I didn't want to piss them off. They said they've heard of people having issues with 87 and malibu advises 89 (confirmed that and see it older posts on here). I checked the oil, as the boat has only been run 3 times since it was last changed and it is black already.

So my questions are:

* can switching to 89 fix this?

* how many oil changes do I need to do once I burn the rest of the 87 out

* I've got nearly 150 hours of 87 on this boat, first time this has happened, have I hurt anything?

* what else can I clean/check/run through this?

* has anyone else experienced this?

Other notes: the boat ran fine all day and has every other day since. it was a little rough but I didn't hear any pinging for the first 2-3min. This was a rare occurance where the boat sat for two and a half weeks since the last time I ran it, but it was fresh gas poured in 30 minutes before we went out. I got the gas from the same gas station it has been filled up from most of the time.

Anyone?

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my understanding is that black soot in the exhaust is from an engine running too rich. Maybe the computer is sensing the lower octane through the knock sensor and retarding timing while advancing fuel creating the rich burn.

I am not sure why you get so much blow by into the oil, but usually it is the sparkplugs that bear the brunt of the harm.

89 octane should help. You might run some fuel injector cleaner for a couple tanks, and change plugs. Wait on the oil until you burn this tank, then change it also. Maybe some other can chime in on damage, but my guess is you did not do any real harm if you did not notice it pinging.

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My white Bu also gets that "sooty" residue on the back. Haven't ever had mine run rough though Dontknow.gif My guess has always been that all exhaust is somewhat black, so I've never really worried about it too much. Just a PITA to clean up everytime, but oh well. I also run 87 octane and have never had a problem of any sort and do not think that 89 would make any difference in the "soot" that you say you're having. Just part of having a white boat I guess.

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Our last '95 sunsetter was white, never got this dirty! not even close and I was far lazier in my cleaning back then.

This was the 3rd or 4th time out in as many weeks, 3rd tank of gas. We've never had it run rough before this and never had that much go out the back.

Thanks for the notes on the plugs and I was already thinking of running a cleaner for a tank or two. The guy I usually go with thought the same thing about it running rich. I'll try these things, get it cleaned up and then if I still have it I'll have th dealer take a peek.

Has anyone heard of the computer updates that might have been a cause of it running rich?

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Is the engine idle rough cold? My buddy had a problem with his '05 where it ran rough at cold idle, burned more gas than it should, had a distinctive rich smell and left the back of his boat dirty. When he described the problem over the phone to the dealer they knew exactly what it was and said it was common. It was a bad regulator in the EFI system - the part and service was about $400.

Edited by CTSunsetter
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By the way, there's about 100% chance your dealer or someone at the dealership is on this site often. Might not want to admit to too much should you have a warranty issue ever.

Whistling.gif

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The 87 octane shouldn't cause sooting. Your engine is runninbng rich for some reason. Is it coming up to temperature ... 160 degrees or higher? A cold running engine is generally the most likely cause of rich running. Do you have a way to check the fuel pressure? That engine should have 60 PSI pressure. If it is high because of a clogged or faulty pressure regulator it will run rich.

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It was cold when it was running rough but does and has never had any issues getting up to temp, just a hair above the exact middle of the temp gauge which I think is 160, so like 163 according to the LCD display. Anything that I can check for the fuel pressure? I have no idea how to check for 60PSI

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Carbeurator or fuel injection? If it's a Holley, it just most likely needs to be adjusted. Any of them that I have had needed it once or twice a year. My Sportster had the soot until I did it, now it seems ok. I only burn regulear gas too, since it is $1.32/liter here. Cry.gif

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By the way, there's about 100% chance your dealer or someone at the dealership is on this site often. Might not want to admit to too much should you have a warranty issue ever.

Whistling.gif

Surely you're not talking about running 87 octane?? :lol:

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mainly just a be careful what you put in print post. Octane is not a big deal, but telling the dealer one thing and posting another is dangerous business if you ever have a real problem. Fingerwag.gif

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mainly just a be careful what you put in print post. Octane is not a big deal, but telling the dealer one thing and posting another is dangerous business if you ever have a real problem. Fingerwag.gif

Agreed Cheers.gif

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A faulty engine coolant temperature sensor would cause an engine to run rich, but would also cause hard starting of a warm engine.

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mainly just a be careful what you put in print post. Octane is not a big deal, but telling the dealer one thing and posting another is dangerous business if you ever have a real problem. Fingerwag.gif

Huh? All the complaints around here about people's dealers, almost all of which are valid, but when we turn it around we're supposed to b.s. the dealers??? Let's be a little more consistent guys.

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just about all 06 indmar engines run a little on the rich side. the epa was looking at co readings in 06 rich mixture lowers co and raises hydrocarbons.

our 05, 06 07 and now 08 gets the white in the back a little black. i would not worry about the oil getting dirty.

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it's not a little black, after 3 people taking 2 x 10-15min sets, wiping the previously cleaned boat with a hand towel will get you a black towel, it's NASTY. There was so much soot/carbon floating in the back of the boat when I started it, it looked like I took a shopping bag of black styrofoam, beat the heck of out of until it was a fine powder and threw it in the lake. It was a lot.

It never starts hard, ever, except when I accidentally let both batteries on the "on" position on the perko and the radio on...then it just plain didn't start :)

Talking with my mechanically inclined carpool buddy he suggested also checking the O2 sensors (not sure where they are on this one) as if they get dirty it could run more and more rich as they get nastied up.

About the oil, it shouldn't be BLACK after 3 days of less than 3 hours of running, that's nuts, it looks like I ran this oil for a whole season already.

I'm seriously thinking of just taking it to the dealer, who by the way I am on great terms with and have nothing bad to say about other than they're a dealer and tend to bend you over a bit on the price because they all do.

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There are no O2 sensors on the Monsoons except the newer ones with the cats. I'd let Tinus take a look at it. They can check easily to see if you have a fouled injector, a bad pressure regulator, etc...

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mainly just a be careful what you put in print post. Octane is not a big deal, but telling the dealer one thing and posting another is dangerous business if you ever have a real problem. Fingerwag.gif

Huh? All the complaints around here about people's dealers, almost all of which are valid, but when we turn it around we're supposed to b.s. the dealers??? Let's be a little more consistent guys.

If you state on this site" I told the dealer X, but did Y, you're screwing yourself potentially. Complaining about dealers is fair game, but thinking they are not on this site monitoring what you may say is naive.

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I had this exact problem last summer with my 06 RLXi. The issue in my case was due to a clogged/dirty fuel filter(s). The boat was going through fuel much faster than normal and I had the black soot around the back of the boat. The explaination that my dealer gave me was that the engine was starving for fuel due to the clogged filter(s) so the computer was increasing the fuel pressure. This was causing the motor to run too rich and obviously increase fuel consumption. Change of fuel filter(s) got rid of the problem instantly. For the record, I have always used 87 octane and never had any problems that I would attribute to octance. Good luck!

Edited by Slalom Frog
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When you did change the filter, did you also do your plugs? and a few oil changes?

I did not change the plugs because I did not run the boat long under those conditions. I did clean the plugs up though. I do not believe that an oil change was done.

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