Thanks for the extra effort LP. Can you clarify, or maybe someone can, what turbulators are in the exhaust manifold or why you might remove them?

They are there to collect condensation and then burn it off. Merc puts them there for a reason.
Some think it adds enough perfomance gain to remove them. Not remotely enough at all IMO to risk the end result of not having them where they are designed to be given their function.

The turbulators are small little restrictors that are placed between the manifold and riser. From what I understand they are to catch and burn off condensation before it can make it's way back into the heads...... They are not to protect against reversion. Not sure if they make a difference or not. It has been discussed in great detail through out the forum.........

There are PLENTY of other Merc Motors that don't have these at all. I am sure if your boat sat in the water all of the time and never got started, condensation would be an issue. However I boat in fresh water, seldom leave my boat in the water. Not to mention the boat is used on average 2-3 a week..... So far so good.

Are you sure you have the correct Amp batteries in the boat? If not the computer goes into gaurdian mode & you will run rich.... just trying to be helpful....

How would the ecm know what the amps are on the battery all it wants to see is that it has 11 to 12 volts to turn on and run

Not sure it matters to the ECM...those 496's needed (required in the owners manual) 1000 cranking amp batteries or they would get a low voltage fault & go into guardian mode.... happened to me... manufacturer put an 800 Amp battery in & I spent a summer trying to figure out the soot problem... dealer told me its the battery... i thought it was a joke... but one new battery later & no soot.... just sayin...

I have 2 group 31 and 1 Group 27 batteries in the boat. That are charged daily on shore power. I have enough cranking power in my boat for most of the marine....

Jay, can you find out if he did that through a dealer or directly with Merc. Mine need to be done to and Merc is not far from me where I could drive there, if that is possible.

Not sure I can buy this. Sure, cranking might put a slight bit more soot, but running, the batteries are not making the juice, the alternators are. I have two Interstate 800s on my twin 496 Victory and the soot is no worse than my single 496 Crownline I had.

I can tell you, I originally called Merc, and they told me I could NOT send the PCM to them. It all had to be handled thru an authorized Merc Mechanic. (This was before I decided to go the whipple route)

He had to go thru the Dealer Jeff. Dealer had to lean on Merc but they did it eventually.

Read your owners manual..... 1000 Cranking Amps is the recommended battery.... Just to clarify I did not say this was the problem... I suggested he make sure he has the right battery.... and he feels he does.... wouldn't matter how many batteries you have if they are not 1000 Amp batteries the computer in the 496's sends a low voltage fault & you go into full rich gaurdian mode.... easy way to find out is hook it up to the computer and look at the error codes...

The only way you would receive a low voltage code is if the battery didn't have enough capacity to supply 12 volts during the entire cranking process. Not at all based on the capacity of the battery. The ECM doesn't care about CCA (Cold Cranking Amps). It only cares that it sees 12 volts. You would need a very weak, small capacity battery that was unable to maintain 12 volts through out the cranking process.

I will put it to you this way. I have enough battery capacity @ 12v to burn my starter out long before my batteries drop below the required 12v necessary to start the boat.

"guardian mode" would also sound an alarm @ the dash and reduce power. Running 69mph (GPS) at close to 5000rpm is running well beyond what guardian mode would allow.

Your soot problem probably went away at right around the 20 hour mark, which was probably the same time you had your battery swapped out. From my research, the 496 was programmed to run rich during the break in period (20-30 hrs).

double post..

Didn't mean to offend. I just know that both of my 496s in the Victory run just fine, and I have two Interstate 800s. I'd know if either went into Guardian mode I think. That shows you right there that I really don't know anything! :lolhit:

Another double post....

My boat had 200 hours on it when I changed the battery.....

Hey I wasn't offended... and I wasn't trying to be arguementative....and I wasn't trying to be a "know it all".... I went through a bunch of BS... told to reprogram this... replace that... installed a new ECU under warranty... two years of non-sense before I bought a new battery & the problem was solved... I was just trying to be helpful by sharing my expirience... I'll leave now....

Did a check on the fuel pressure and at idle it is just shy of 40 psi and at WOT it is at around 43psi. Called my Merc Mechanic and he told me that was about right. So the little bit of soot that is left on the transom, I am going to say is being caused by the side skirts of the swim platform causing a vortex efect that is pulling the exhaust back to the transom. As mentioned earlier I have plans to pull that platform and switch for a tublar platform over the off season..

GRH, I understand completely. I have done things that I thought "no way this is gonna fix it", and found out it worked perfectly. I truely think these modern, computer controlled, finicky engines have a mind of their own. You simply stated personal experience, and I thank you! Sometimes, the improbable fix works.

Did the reflash get rid of the gas floating on the water at idle?