I think that my 496 HO run a little rich???

[I DIG IT !]

Well do any of you pees have the same problem?? I have owned a few boats in my life time, but the new boat seams to leave alot of the black shit on the back of the boat. Do all HO's do this or just mine. My last boat hat a 502mpi and left some but not this much. And my bor has one too and leaves very little????

[CornWater]

Run 87 octane instead of super...

[I DIG IT !]

are you sure, does it make it run better??? or i mean leaner. because i allways run the good stuff

[MR.rvrluvr]

are you sure, does it make it run better??? or i mean leaner. because i allways run the good stuff
merc recomends it.....the computer will richen it up to compensate for the hotter burn .....how many hours .....I heard that merc sets the computer to run rich for 20 hours break in time then the black sheet goes away.....

[CornWater]

Doesnt matter how many hours, it will still "soot" up with super in it. I know mine does, and I have about 130 hours.

[Phat Matt]

Run 87 and call it a day.

[OutCole'd]

Doesnt matter how many hours, it will still "soot" up with super in it. I know mine does, and I have about 130 hours.
Yep, same here with a 525 also. Regular works fine, no problems.

[Sigus]

I run a 525 and 87. Still get the soot. My Bimini cover was red and is now stained black.
Looked into reflashing the computor and was told not to do it as it would cause diffrent problems.

[purrfecttremor]

I also run 87 octane with 130 hours and the back of the boat looks like shiat..
Merc says its all good :mad:

[blown65]

We have about 43 hrs on hour HO and it still gets black on the back. 87 here as well. I can actually put twice as many hours on my ski boat and it will be totally clean.

[HTM SR-24 Mitch]

I have about 270 hrs and I have a procharger and I get very little black soot.

[ManOnTheRun]

don't listen to this guy. :D
Doesnt matter how many hours, it will still "soot" up with super in it. I know mine does, and I have about 130 hours.

[I DIG IT !]

Wel i have 75 to 80 hours on it now. But i have allways ran super or at least mid. Maby I'll try the old 87'er and see what happens

[Mandelon]

You need to run WOT more often... :D
I think it may just be the luck of the draw, my HO doesn't soot at all. I have this bottle of Transom Sauce just getting lonely there in the shed.

[Beer-30]

I have lots of soot also.
The HO is optimized for 87 octane. Higher octane can technically make it run at less than peak.
Dyno test showed no difference in HP between 87 and 92. You are wasting money with anything other than 87.
496s are set up quite rich to avoid damage. You can spend $1500 with ASM and they will provide a new MEFI-4B ECM, harness, and tune. Probably a handfull of HP gain, but most of all it will be laptop tuneable and no more soot.
Or, headers are a nice first step to lean it out a little. Should get rid of most of the soot. Plus, several HP gain.

[NuckinFutz]

496 and soot are one in the same. Run it for a half hour and scrub it for 10 minutes, that's my story and I'm stickin with it.

[I DIG IT !]

thanks for all the advice:) I'll start with just running 87 and see if it changes.

[Zimm944]

I run 87 and no black problems at all. I had to run mid grade while on the river last trip and black crap all over the back. Run 87 save some money, and less cleaning.

[Throttle]

I recall someone saying some changes were made to the '05 and newer HO's that reduced this nasty build up. I run regular unleaded all day long and after 250 hours I still do not have any of that crap on my transom...

[soupersonic]

496s are set up quite rich to avoid damage. You can spend $1500 with ASM and they will provide a new MEFI-4B ECM, harness, and tune. Probably a handfull of HP gain, but most of all it will be laptop tuneable and no more soot.
Dont go down this road to stop getting soot on your transom,i did and it cost me a whole season and about $12,000 last year. I had them tune my ECM's and they leaned them out so bad i burned a hole in the #8 pistons. I didnt know any better and found out i should have put the bung in the header for an O2 meter. They didnt tell me this, only " I have a program i think you will like"
The problem with the AZSM mefi controller is it works awesome,ive seen it in action but you have to have the bung in the header , a laptop, an o2 meter plus their Ingenious program. More like $2500 (if you already have a laptop) when it all said and done. That pays for alot of transom cleaner

[charlyox]

I run 87 and very little soot. Don't waste your money on anything higher.

[Dribble]

If I run 91 I get balck soot. You should run 87.

[phebus]

Run 87, and take out the turbulators. Won't cure it, but will make it better.

[Not So Fast]

HP 500 here and my son also, his is worse than mine. Sometimes worse than others, get over it and carry a bottle of a good Simple Green 50/50 mixture and a long soft bristle brush and just clean it a little more often. Its bio-degradable. Octane didnt make any difference so run the recommended 87. Soot rules!!!!!:D NSF

[BigDoug]

Rick, what is this "turbulator" you speak of ?

[phebus]

Turbulators are cone shaped restrictors that are in the 496 exhaust riser that are designed to trap moisture from the returning to the valve train. They are highly restrictive and unnecessary in most boats. Removing them frees up your exhaust and allows your boat to breathe better. Do a search on OSO, and you will find some posts from Ray at Raylar talking in detail about them, their purpose, and what boats can remove them without issue.

[Beer-30]

Dont go down this road to stop getting soot on your transom,i did and it cost me a whole season and about $12,000 last year. I had them tune my ECM's and they leaned them out so bad i burned a hole in the #8 pistons. I didnt know any better and found out i should have put the bung in the header for an O2 meter. They didnt tell me this, only " I have a program i think you will like"
The problem with the AZSM mefi controller is it works awesome,ive seen it in action but you have to have the bung in the header , a laptop, an o2 meter plus their Ingenious program. More like $2500 (if you already have a laptop) when it all said and done. That pays for alot of transom cleaner
Oh, I wouldn't even attempt it without an O2 sensor and meter. As you found out, you basically can't safely run an adjustable system without some sort of meter to know where you're at.

[Beer-30]

Turbulators are cone shaped restrictors that are in the 496 exhaust riser that are designed to trap moisture from the returning to the valve train. They are highly restrictive and unnecessary in most boats. Removing them frees up your exhaust and allows your boat to breathe better. Do a search on OSO, and you will find some posts from Ray at Raylar talking in detail about them, their purpose, and what boats can remove them without issue.
http://www.hotboatpics.com/pics/data/500/5472DSCF1482-med.JPG

[dunaholic]

Turbulators are cone shaped restrictors that are in the 496 exhaust riser that are designed to trap moisture from the returning to the valve train. They are highly restrictive and unnecessary in most boats. Removing them frees up your exhaust and allows your boat to breathe better. Do a search on OSO, and you will find some posts from Ray at Raylar talking in detail about them, their purpose, and what boats can remove them without issue.
How would I find this link? I would like to know if I can safely remove them.

[Beer-30]

How would I find this link? I would like to know if I can safely remove them.
Search here on "turbulators". Several of us chimed in on the removal process.

[MEFIburn]

Oh, I wouldn't even attempt it without an O2 sensor and meter. As you found out, you basically can't safely run an adjustable system without some sort of meter to know where you're at.
Beer-30 is absolutely right. Preferably run a wide band O2 sensor and see where your air/fuel ratio is. You can scan and data log your engine and see exactly what it is doing at any instant. If your engine is running a MEFI controller, do a search for MEFIburn on google.
These EFI engines can run optimally with any grade of gas, it is a matter of setting up the spark and fuel tables correctly in the engine controller. No black smoke, no rich or lean conditions, but it will take effort for an optimal tune with great power and better fuel economy. Think of it as having to mess with the carb adjustments and distributor advance curve until it was right, only now you do it with a laptop and a cable to the wiring harness on these EFI engines.

[Hotcobra270]

I recall someone saying some changes were made to the '05 and newer HO's that reduced this nasty build up. I run regular unleaded all day long and after 250 hours I still do not have any of that crap on my transom...
250 hours! :jawdrop: :sqeyes:
Is your boat your primary home Cam?

[Powerquestboy]

I have the same soot problem with my 502 EFI and I always run premium. Does the same go for this motor? Should I try to run 87?

[kcvega]

I removed the rubber flappers from my exhaust tips on the outside and almost eliminated all soot problems. Also running 87.

[Beer-30]

I don't get why you people want to run other than 87 in less than 9:1 motors. Plus, they have knock sensors for protection. These motors will damn-near run on water.

[soupersonic]

Oh, I wouldn't even attempt it without an O2 sensor and meter. As you found out, you basically can't safely run an adjustable system without some sort of meter to know where you're at.
Thats the whole reason i bought the program to tune the mefi 3's and 4's.Ive got the laptop and the wideband O2 meter. I can help out someone who needs a tune so they dont have to go thru what i did.You need either the bung in the header or we can put it on the dyno :) That mefiburn is expensive and they arent telling you in order to recalibtrate your most likely going to have to dump your existing program and reload a program thats close enough to get it running so you can tune it. Most ecm's are either locked or pw protected,i have most of the stock programs and a few others

[KLEPTOW]

Thats the whole reason i bought the program to tune the mefi 3's and 4's.Ive got the laptop and the wideband O2 meter. I can help out someone who needs a tune so they dont have to go thru what i did.You need either the bung in the header or we can put it on the dyno That mefiburn is expensive and they arent telling you in order to recalibtrate your most likely going to have to dump your existing program and reload a program thats close enough to get it running so you can tune it. Most ecm's are either locked or pw protected,i have most of the stock programs and a few others
What program are you using to program the Mefi3 ECM?

[shueman]

Get some Transom Sauce...:D

[soupersonic]

What program are you using to program the Mefi3 ECM?
The program Mercury uses. Delco Electronics.You can change any parameter you want, but you mostly need to to adjust the fuel maps and spark tables on a N/A motor and then boost reference it if its blown.You can adjust idle speed,rev limiters as needed. You can adjust it with the air/fuel meter so its perfectly tuned at 200 rpm increments.

[Raylar]

Thought I would add a little "meat" to this discussion. In regards to Octane, rmember Octane does not make power! It only slows the fuel burn to overcome knock. when an engine is built and calibrated to use 87 octane and you use 91 or higher octane you do not make more power. this higher octane burns slower and hence a lot more can go out the exhaust pipe poorly or altogether unburned and add soot to a transome as well as help create fuel wash on the walls of the cylinder. Use the manufacturers recommended fuel octane!
Next, almost all of todays high performance hulls have extended transoms in their designs. When the exhaust exits out under these extended transoms their is always a negative pressure area underway under these transoms and as the exhaust is exiting its being pulled back by the negative pressure to the back of the transom and tips and there it deposits and sticks to the clean fiberglass and chome. there is a negative pressure behind just about any high speed hull when underway but the extended transoms make the problem worse.
Lastly, todays new fuel blends have a lot of crazy "chit" mixed into them to suppossedly reduce emissions and not all of this "chit" burns in the engine.
We do a lot of dyno work on both pump gas and test fuels and I can see the black residue on the headers, combustion chambers etc. from pump gas, its horrible!! When we load race fuels, wholla! black "chit" gone! Also remember that if the new vehciles that run this pump gas were running air fuel ratios like we need to run in performance marine motors (11.0 to 13.0 to 1) instead of the 14.7 to 1 they run the black "chit" would be all over the back of our cars and trucks!!
Thought these little bits might help explain the problem!
Regards,
Ray @ Raylar