PDA

View Full Version : Merc 496 Mags smoking



River Ric
07-09-2002, 08:54 PM
I bought a new Cobra 23' Razor at xmas time. I love the boat and the new engine, except for the black residue that is left on my white transom at the end of the day. I have tried different gas brands and octanes to no avail.I have contacted Mercruiser and they say that they have no fix at this time. Cobra has done all the can including installing a new K&N filter. I have taled to Hallet boaters, Eliminator, and Essex. All have the same complaint to some level or another. If this really is a problem for the 496 Mag and the 496 Mag HO, I think we need to all get on their butts to get this problem fixed. I didn't spend all that money on a performance motor that is going to leave my boat a mess everytime my family and I go to the river. Please respond if you have had the same issue. Thanks

gnarley
07-10-2002, 08:36 AM
What fuel are you using?

SUPERCREWJOHN
07-10-2002, 10:47 AM
How many hours are on your Boat? More than 20? I believe there was another thread on this topic...
I believe also that Arizona Speed and Marine was able to Modify the ECU to get this problem to go away..

playdeep
07-10-2002, 11:38 AM
Mercruiser sets up all of thier packages to run rich because of the warranty factor.Supercrewjohn is correct,if you want to get rid of the blackened transom send it to Arizona Speed &Marine.BTW you will also notice better mid-range response.

River Ric
07-10-2002, 08:21 PM
Originally posted by gnarley:
What fuel are you using?
It doesn't matter what fuel I used, it was all the same. Texaco, Shell, Arco, Chevron, Ubion 76. Even some of the no-name guys. Nothing changed. Even different octane did not clean it up.

River Ric
07-10-2002, 08:25 PM
Originally posted by SUPERCREWJOHN:
How many hours are on your Boat? More than 20? I believe there was another thread on this topic...
I believe also that Arizona Speed and Marine was able to Modify the ECU to get this problem to go away..
I already have 36 hrs. on the motor. It already had it's 20 hr. service 2 months ago. It has smoked from the first day I put it in the water.

Havasu_Dreamin
07-10-2002, 08:58 PM
Originally posted by River Ric:
<snip>
River Ric, aren't you the tall guy in the cowboy hat outside the Pioneer in Laughlin?? http://www.planetsmilies.com/smilies/happy/happy28.gif http://www.planetsmilies.com/smilies/happy/happy28.gif http://www.planetsmilies.com/smilies/happy/happy28.gif
Just messing with ya. http://free.***boat.net/ubb/biggrin.gif
HD
[This message has been edited by Havasu_Dreamin (edited July 10, 2002).]

In2Deep
07-11-2002, 07:23 AM
Ric:
I've got a brand new 496 Mag HO in my Nordic 28 Heat -- and definitely had the BTP (Black Transom Plague).
Was told it was normal, and that it would dissipate naturally. Was also told a K&N air filter swap would help alleviate the problem.
Did the K&N - and saw an immediate improvement. I'd say about 50% reduction in residue.
When I pulled the boat out of the water this 4th holiday after 3 days on the water, I was pleased to see that residue was not that bad.
I'm at 32 hours now.
I'd say to wait it out slightly longer -- it should improve. And make sure you're using 87 Octane -- nothing higher.
dh

River Ric
07-11-2002, 10:22 PM
Originally posted by In2Deep:
Ric:
I've got a brand new 496 Mag HO in my Nordic 28 Heat -- and definitely had the BTP (Black Transom Plague).
Was told it was normal, and that it would dissipate naturally. Was also told a K&N air filter swap would help alleviate the problem.
Did the K&N - and saw an immediate improvement. I'd say about 50% reduction in residue.
When I pulled the boat out of the water this 4th holiday after 3 days on the water, I was pleased to see that residue was not that bad.
I'm at 32 hours now.
I'd say to wait it out slightly longer -- it should improve. And make sure you're using 87 Octane -- nothing higher.
dh
Hey thanks, I just had the filter installed today. I will pick up the boat Friday and give it a good run this weekend.I will keep the 87 octane too. Later!!!

River Ric
07-11-2002, 10:24 PM
Originally posted by Havasu_Dreamin:
River Ric, aren't you the tall guy in the cowboy hat outside the Pioneer in Laughlin?? http://www.planetsmilies.com/smilies/happy/happy28.gif http://www.planetsmilies.com/smilies/happy/happy28.gif http://www.planetsmilies.com/smilies/happy/happy28.gif
Just messing with ya. http://free.***boat.net/ubb/biggrin.gif
HD
[This message has been edited by Havasu_Dreamin (edited July 10, 2002).]
Actually I am. Thanks for askn!!!!! River Ric

shockwaveharry
08-09-2002, 05:10 PM
I had the 496 HO with the BTP :D as well. At 5 hours I installed a set of lightning headers and saw an immediate improvement. No more sooty transom. I also picked up 4 or 5 mph on the ol' GPS. However, with the exhaust in place, I saw no improvement with a change in flame arrestors.

brewski
08-22-2002, 04:59 AM
Shockwaveharry, I have the 496HO wondering how well the lightning headers installed. I've installed headers on 454,s they said just bolt on, that was bull#$&^. Did you have to remap your ecm? Sounds like good HP gain.

shockwaveharry
08-22-2002, 04:28 PM
I installed a used set of Lightnings because at that time the engine was so new no one had anything available yet. Installation was straight forward, I modified the mounting locations of the oil filter, ECM mount and shift linkage mount (those things would be included with an exhaust system by now I would imagine). I made several power runs after installation checking the plugs for any signs of detonation. No need for ECM reprograming (a moot point since no one programs the Motorola computers yet that I know of, certainly not last year). The results were well worth the work. :cool: