Mercury 700sci 2009 model, manifolds
 

Hi guys,

my Cig 42x 2009 model, needs replacement of at least one header & tube. It has 219 hours, and is 5 years old already. Because I bought it just now, I am not aware how it was preserved as ehcaust system before so I am thinking, to avoid any internal links to change it complete for both engines.

I have seen that there are 3 choices :
1)Stainless marine
http://www.stainlessmarine.com/produ...c-replacement/
2) Custom Marine
http://www.custommarine.com/headerapps/genxheaders.php
3) OEM Mercury

Stainless marine is different to the others significantly since they use one big tube instead of a usual manifold with big curves for all 4 tubes.
Custom marine seems very close to OEM Mercury design, I am not aware if they are completely the same.
I use the boat only in salt water but will take extra good care of it (always fresh it afterwards and drain the exahust etc).

What do you suggest in terms of longetivity and performance?
Any idea of (total) cost for complete exhaust system for both engines? I imagine it is seriously painful..!

I would not use the Merc spec OEM as they are known to go cheaper on the build quality than the custom.
I have had both Stainless Marine and CMI over the years and like them both. That said, all my friends who have the 700's run CMI.

I'd go with Stainless Marine, I know they aren't as good looking and you loose a little bit of Bling. But I'd rather loose some Bling then a motor. Stainless Marine make just as good Horsepower. I have seen them candy coated in a variety of colors and I have also seen the manifolds polished. They look great to me and you will have piece of mind. There are about 100+ threads on CMI failures. Try to find one on stainless marine failures. Just saying

We just switched from CMI to Stainless Marine Gen 3 this year! Very happy with the quality and customer service!! Looking forward to not having to take headers off and pressure test them all the time.....

I have spoken with people that have used Stainless Marine for over 12 years in salt without any problems!! That was the final deciding factor for me!!

OEM Merc headers are made by CMI to Merc specs. They are actually lower quality than the CMI Gen X replacement headers.

If I remember correctly, you are in Europe and were asking about extended salt water use for long periods of time.
If that is the case, I would definitely go with Stainless Marine over CMI's.

I would imagine, you are looking around $10000 US for a complete exhaust system.

Thanks Guys. Indeed Griff i am in Europe and I do only salt use.

How often per year do you pressurize the exhausts? Every year once (?), or every X hours?

Do you lose power with Stainless marine?

I was pressure testing my CMI headers after every poker run. One was leaking and I had it welded up but was paranoid the others were right behind with leaks.

Gen 3 Stainless Marine system is supposed to make more power..

I would say it depends on how old the exhaust is. If used in salt and the exhaust is more than 3 years old, I'd say at least every year.
You will not lose any power with Stainless Marine's over the CMI's.

I switched over to Stainless Marine gen 3. While not as flashy no more headeraches.
No collector leaks, 02`s stay dry, easier header bolts to access, more bilge room, longer tails help reversion, etc etc ..all around win.


http://33outlaw.zenfolio.com/img/s12...92116456-3.jpg

Are yours the original headers? Do they have the cool Coller on them? (about 1/4" of space on the back side of the mounting flange where the weld for the tube starts vs right up against the back side of the flange).
There is a guy in the Cleveland area that is awesome at fixing them. Name is Bob Anspach. Does a bunch of them and never seen one crack again at least in the same spot. If they are corroded a lot he probably won't be able to do anything for you. It might only be one or two spots and can fix them. He can also check the ones that are ok and hit any spots that they usually fail in.its worth a shot.