Mercruiser 4.3 V6 - Manifolds, Risers & Elbows condition

[AndreMaxum]

Hello all,

I would like to have your opinion about the actual condition of my exhaust system.
I started to see some rust in one manifold and I decide to remove and inspect the both manifolds, risers and elbows.

After disassembly all...I realize that they are are in different conditions and I don't know why...is it common to have different degradation between both sides? (you can see the difference in attached pictures)

As you can see in the pictures, the left side is in worst conditions than right side. In left side I already removed some rust.

My big question is...can I reassembly this parts with new gaskets for one season more (3-4 months in salt water)? What are your opinions?

Thank you!!!

 

[alldodge]

Appears someone had trouble with the left side and replaced them some time back.
Don't think I would use the right side

 

[AndreMaxum]

Appears someone had trouble with the left side and replaced them some time back.
Don't think I would use the right side

Thank you for your comment!

About new kit, which brand do you recommend?
I see some brands but I don't have any idea which one should be better for salt water.

HGE is the actual brand that I have...but I saw HOT, RecMar, H2O,... could you give me your opinion ?

 

[achris]

I've had HGE on a few customers and they seem better than Sierra or GLM. The 'best' is Merc. But if you are planning on changing the whole thing (manifolds, risers and elbows), then upgrade to dry-joint... And yes, you can upgrade one side at a time to dry-joint if you want to spread the expense.

Chris........

 

[Lou C]

It’s always risky in salt water due to the speed within which corrosion happens. Those left side risers look too pitted to seal properly. The others I can’t tell because the old gaskets prevent you from seeing the sealing surfaces. You want non-pitted flat and level sealing surfaces. They can be cleaned up carefully with a file or if you have access to an automotive machine shop they can be cleaned up on a belt sander. However depending on how much internal corrosion has happened you can still have rust through even with the better dry joint system. Here in Long Island salt water we usually replace them between 5-7 years. Doing it this way I have never had water in a cyl from leaky exhaust. People who try to get “just one more season” sometimes lose that gamble and wind up paying for a new engine!

 

[achris]

.... Here in Long Island salt water we usually replace them between 5-7 years....

My dry joint manifolds are still original from 2006. The elbows I did about 8 years ago, and they are still good too.

Chris.......
-32,116

 

[Lou C]

OEM Merc?
that is really excellent!
I had the batwings (one piece) before and there was no way to tell how thin they were getting inside. And my boat has always been moored so no way to flush. I’ll see if the Barr aftermarket lasts the same or longer than the OMC original equipment.

 

[achris]

OEM Merc?

Yes, 2006 manifolds on a 2006 engine.

I had the batwings (one piece) before and there was no way to tell how thin they were getting inside. And my boat has always been moored so no way to flush. I’ll see if the Barr aftermarket lasts the same or longer than the OMC original equipment.

Batwings were a disaster from day one.

 

[Lou C]

Believe it or not I had those from 2002 when I bought it (boat came from the mid west their were original 1988 OE) it till 2017 when I converted to the 2 piece style and never had any of them leak. I changed the OE ones in 2004, then again in 2011. That set I left on till ‘17 when I replaced the cyl heads (unrelated to exhaust).
I heard there were casting problems with both the OMC and Merc versions of these. I can say the cooling passages in the Volvo style 2 piece are bigger and they run cooler.

 

[chartersj]

My dry joint manifolds are still original from 2006. The elbows I did about 8 years ago, and they are still good too.

Chris.......
-32,116

That's good to hear. Mine are still original on my 2007 mostly salt use. Risers are stainless steel with dry joint. Been considering pulling them off to test