33outlaw

[[email protected]]

Hey Guys, Any feedback re: excessive carbon build up on transoms on these new 496's. Mercury rep seems to think thats normal. DONT KNOW WHAT HE'S THINKING!!!!!!!!

I HAVE GOT 72 HRS. AND IT IS STILL THE SAME SINCE DAY ONE.

WHEN DOES IT GET BETTER?

ANY CHIP PROGRAMMERS OU THERE?

THX. GREGG

enticer

Believe it or not......it is normal. Merc runs their motors real rich...so we don't blow them up as quick and it helps run the motor cooler. Also the type of gas can contribute to it somewhat. I bought a set of computers and had a shop set up a different program....that helped the carbon problem (about 85-90%) and helped the performance of the boat

33outlaw

HEY THANKS FOR THE REPLY
I HAVE BEEN ONLY USING 87 OCTANE AND NO OTHER REVISIONS
DID YOU HAVE YOUR CHIPS REPROGRAMMED? OR BOUGHT ALL NEW? AND WHERE?

In2Deep

Chiming in...

I've also heard it's normal. I had reasonable build-up the first 25 hours on mine. Seems to be dissipating. 87 octane only is the right approach.

Also, just replaced stock flame arrestor with a K&N this weekend. I've heard that this swap helps with carbon -- but too soon to tell definitively. Sounds good, though.

dh

Macklin

Yup.....same here. I had it real bad for the first 25 hours or so. Since then I have seen very little build up.

CigDaze

It's normal.

It had me worried for a while as well, until I asked my High-performance Merc expert about it. He said no problem, just live with it. The first 25 or so hours were the worst, but it has gotten better since then.

I just spray some Simple green on the transom after each day out(or weekend) and it comes right off very easily. Good wax also helps.

The crappy thing is that my swim platform also gets it pretty bad from the wind vortices...makes for some pretty dirty knees and hands from swimming.

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Here's one for you guys...Mine seems to be much dirtier on the port side. Is this what you guys are seeing? I heard it's got something to do with the way the cooling water is plummed through the exhaust...

AZDominator

Same here, I have 2 496 Mag HO's. First 20-30 hrs build-up was bad, particularly above 4000 RPM. Between 2500-3500 I would get very little. Now I have 70 hrs on them and I get very little residue.

teckersley

My $0.02

Same problem. The first 25-30 hours was terrible but the more hours I put on it, the better it gets. I just keep a small spray bottle of simple green in the boat for cleaning while swimming. Otherwise, this s%#t gets everywhere.

Racing_Fan

Baja Daze,

The port side on my boat has been dirtier than the starboard since my 10+ hour mark. My transom was extremely dirty from 0-15 hours, and it has lightened up a bit lately. I'm wondering too if the port side sees more soot because of the cooling water plumbing...

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For all you 496'ers with single-point air drain systems, be careful at the start of the day after you release the pressure from the system...I throttled up one day and cruised for 2-3 minutes and then found a bilge full of water and a very hot port exhaust header. It seems the system still had some slight pressure in it and part of my cooling water was leaking into the bilge thru the drain gate on the port side.

-Racing_Fan

CigDaze

Thanks for the tip Racing_Fan!