New Exhaust Manifold surface prep? 4.3 Mercruiser

Tmakaro

Seaman
Joined
Nov 22, 2011
Messages
66
I just purchased new exhaust manifolds and risers for my 2010 Bayliner 192 with a 4.3L Mercruiser.
The manifolds are painted where the exhaust gasket goes and some of the paint has chipped off. Do I need to chip off the rest of the paint?
 

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ESGWheel

Chief Petty Officer
Joined
Aug 29, 2015
Messages
534
Lots of different opinions out there. I ended up cleaning up the paint on mine, see this thread > link
 

IslandExplorer

Chief Petty Officer
Joined
Oct 21, 2019
Messages
468
Ford used to run iron to iron with no gasket on some engines exhaust manifolds believe it or not. Iron under pressure can be a great sealing surface that won't burn away when smoking hot unlike paint. I'd take that paint off with a flat file. My exhaust manifold directions actually rec to do this before install to be sure mating surfaces are totally free of any raised burrs from banging around or whatever. So I think you're totally safe removing it, just don't go overboard with an angle grinder to 'save time' and accidentally scar up your nice new machined surfaces under there.
 

cyclops222

Lieutenant Commander
Joined
Mar 21, 2024
Messages
1,962
I have 12" long file that is just for removing paint. I rub chalk into the clean file teeth FIRST then use the file to remove paint I also have a File Cleaning Card to clean the file teeth as needed.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
50,224
if the surface is flat, bolt it up with a new gasket and go

if the surface isn't flat, then address that first.
 
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