So how has the reflash worked out for you? Is there notable difference on the transom...I have the '03s and it's a daily battle to keep it clean.

any info on how the ecm is working out for you?

Merc just exchanged PCM's with a friend of mines 496 Mag.
No cost and the soot went away. Your Dealer should be able to push Merc on it if it has not been updated previously.

With the price of fuel these days why waste the extra money on 91 or93 octane. I read an article on here from a gentleman in texas that does installs for whipple, he did extensive testing with dyno sheets provided that prove a stock 496 will only make 1 or2 more hp with the higher octane. My 09 496s sooted up a little but after about 20-30 hrs they cleaned up & havent had a problem since

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Ok Low PSI.. It has been over 2 months. It is not in anyone's interest if you come here looking for advice and then don't follow up with results. Info sharing is a 2 way street here. I think we should give you 1 week to post a follow up or have everyone bombard your inbox weekly .

Chris

Relax Bud. It is summer and I am out enjoying my boat....... And if you choose to Bombard my inbox, it only accepts a few messages, then it is full so it really wouldn't hurt all that much......

Anyway on to the results. I ended up going with the stage II Flash instead of the "Stock" flash. The Stage 2 flash uses a 120 t-stat and 92 octane. That combined with the fact that my boat was running too rich to begin with has made a HUGE difference in perfromance. Before the Flash I could hit 65 on the GPS with a Full Tank of Fuel and myself in the boat. After the Flash I have sucessfully tagged 69 on the GPS (with a full tank of fuel). Mid-range pull is HUGE compared to before and planing time is reduced by a couple of seconds as well. I do still have a bit of soot, because I have to run a higher octane to prevent detonation. However the soot is a very fine soot, where it was very greesy and thick before the re-cal. The soot is much easier to clean now. Before it took a good degreeser to remove it, now simply soap and water will do the trick. I think what I see now is a result of the Swim Platform causing some sort of weird vortex that is pulling the spent exhaust back up against the transom. I have plans to switch to a tublar platform next season so I will stick it out for the last 4 weeks of the Michigan boating season..

Thumbs Up
 

Ok Thumbs up to Low PSI for the info.. Not only did you tell us about the soot clearing up but that is an impressive performance gain. This is way info sharing is suppose to work...

Chris..

It is certainly a waste to run 91+ with a stock cal, but with a modified cal, its the way to get more HP/TRQ.

More timing, different injector timing, different coil dwell, modified idle settings, higher rpm limit, relaxed codes such as water psi and standard ones such as fuel level, pitot tube psi, trim level.... We maximize for 91 or better octane, Mercury worked with 87 octane and after a few years, finally got the fuel curve semi-ok but left power on table because they target low octane.

I am by no means claiming that everyone will see the gains I did with a Stage II ECM Flash. There are a few factors involved that I would like point out. First off, my boat was running the Original 2003 ECM Flash and was running very rich, so the motor was most likly not performing at it's best. (I was only able to get around 4600 RPM at WOT). So the Stage II flash solved the way over rich issue created by Mercury. Now add to it, the Stage 2 with its changes brougth the performance up to and beyond. Add to that the "pad" running surface of the Velocity. I also removed the "turbulators" from the stock risers.

So all factors combined to a 4-5 MPH difference. I am sure if I pulled the 2 group 31 batteries out of the engine compartment (I currently have 1 group 27 and 2 group 31), pull the 40lb subwoofer enclosure out from behind the port-a-potty, pull the 80lb amp rack out of the cabin, and run a much lighter fuel load there is probably a few more MPH left in it.

There is a noticable difference in the idle with the stage II flash. Check out these Youtube videos of before and after....

This is last season before the ECM Flash:
[YOUTUBE]http://www.youtube.com/watch?v=4Jph8HmoIn4[/YOUTUBE]


And After Stage II ECM (and removal of "turbulators from exhaust risers, no other changes):
[YOUTUBE]http://www.youtube.com/watch?v=VZWLZkTa_m0&feature=related[/YOUTUBE]

Yes there have been considerable changes to the appearance to the boat, but I assure you it is the same boat in both videos. The interior has been replaced, name on transom changed (different font and colors) and speakers were added to the transom. and yes that is my fat a$$ starting the boat...