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Offshoreonly.com (https://www.offshoreonly.com/forums/)
-   General Q & A (https://www.offshoreonly.com/forums/general-q-20/)
-   -   496 Mag HO (https://www.offshoreonly.com/forums/general-q/96113-496-mag-ho.html)

mwdill 06-01-2005 05:36 AM
Re: 496 Mag HO
 
Originally Posted by FOUNTAINATLAST
I get soot with 91 or 87 octane, doesn't matter.
is it worse with 93?

docmanrich37 06-01-2005 05:57 AM
Re: 496 Mag HO
 
Had the same with my 496 on the baja.merc rep said not to use 93 and when i put 87 in it i had less soot on the back.see if your local merc rep can reflash the computer and it will reduce the soot problem a little.at idle i would put on capt.choice so it would go out the prop instead of on the back of the transom.

FOUNTAINATLAST 06-01-2005 09:36 AM
Re: 496 Mag HO
 
I've checked locally about having my PCM reprogrammed, everyone tells me Dustin at whipple is the only one that can do it yet. Just curious if it helps or is it a waste of time and money!!!

saubouin 06-01-2005 09:53 AM
Re: 496 Mag HO
 
Originally Posted by mwdill
what octane are you using?
since i started running nothing but 87 i don't have that problem anymore.
When I first got the boat I was using only 92 Octane and had no noticeable soot. I have since switched to 87 Octane at the recommendation of several forum members. I now have more soot. But I don't think this has anything to do with the octane switch. Everytime I take the boat out I hardly do any idling. It wasn't until last week when I had to do long periods of idling that the soot buildup became VERY noticeable. So I think it's more a function of low speed idling and the PIG RICH A/F ratio's on the stock PCM.

FOUNTAINATLAST 06-01-2005 09:55 AM
Re: 496 Mag HO
 
Originally Posted by mwdill
is it worse with 93?
We don't have 93 octane in AZ only 91

mwdill 06-01-2005 09:01 PM
Re: 496 Mag HO
 
Originally Posted by FOUNTAINATLAST
We don't have 93 octane in AZ only 91
:eek:
probably the same.
gas is getting worse every year.

mobilecal 06-02-2005 10:16 AM
Re: 496 Mag HO
 
what happened to BHOCKETT? Like to know what the outcome was

FOUNTAINATLAST 06-03-2005 12:57 AM
Re: 496 Mag HO
 
Paging BHOCKETT, whats the update how did she run???

boatfreak 06-06-2005 10:31 PM
Re: 496 Mag HO
 
Well I pulled mine off tonight. I am going to get them polished and then I'll let you know if there is any change. I will say I will be shocked if there is a difference. What is the story on the two and a half inch horn on the end of the riser? I have never held a riser from any engine in my hand before so that may be a dumb question but I just thought it too looked like a bottleneck. My thought would be none of these things would make a hell of a lot of difference unless you start trying to make some more horsepower.

FOUNTAINATLAST 06-06-2005 11:11 PM
Re: 496 Mag HO
 
Originally Posted by boatfreak28
Well I pulled mine off tonight. I am going to get them polished and then I'll let you know if there is any change. I will say I will be shocked if there is a difference. What is the story on the two and a half inch horn on the end of the riser? I have never held a riser from any engine in my hand before so that may be a dumb question but I just thought it too looked like a bottleneck. My thought would be none of these things would make a hell of a lot of difference unless you start trying to make some more horsepower.
Be careful everyone that says that they'll post there finding have never returned???? :eek: Keep us up to date. :D


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