I have Emi Thunder manifolds and stainless risers. It's a dry joint system. I they came on my boat when I bought the boat. I have been running them 2 yrs now. They seem well made. No issues here.

My main issue is the newer EC motors have the manifold and collector. So, I'm having a hard time finding an aftermarket setup that will fit and bolt up to the existing exhaust elbows. I'm leaning towards just buying an OEM manifold for the side that is cracked and seeing what the insides look like to see if I can get another year out of them.

Has anybody sent their cast manifolds and risers to get acid dipped to clean out the rust / corrosion? If so, who did you use?

Don't see cleaning the inside of the water jackets doing anything other then make it easier to see. If its rusty that's normal and it's not going to hurt anything. If the walls look thin then they are. Salt water manifolds will last about 7 years

Well I spent half the day pulling the port side manifold and exhaust collector off. The good news is the crack in the manifold is on the outside just above where the water comes into the manifold at the bottom. The crack is not through to the inside.

The bad news is one of the water ports on the exhaust collector is clogged completely with rust. So, it looks like I'm replacing the manifold and riser. So now the question is if I can find a decent aftermarket setup for a cheaper price. Seems like $1500 or so for each side and that is just crazy.

What is your serial number?
Is the catalyst still good inside the manifolds?

1A352940

Catalyst seems ok.

Best I'm finding is $1245.42 each side x2 = 2490.84

manifold 8M0045258 amazon $555.43 free ship and comes with manifold gasket
elbow gasket 27-8M2003931 ebay $59.41 +2.94 ship
collector 866391T02 ebay $538.70 + 4.95 ship
collector gasket 27-866390 Perfprotech $83.99 + ship??

The newer style manifolds cost a bit less (not much), but to use them you would also need new catalyst which is another 1100

I was thinking of ditching the catalyst all together and getting one of those cat eliminator systems. How much cheaper was the newer style?

The collector and manifold are one piece and run around 500 each side, so lest say saving 500 each side. The other thing is your current riser/elbow will not work with the new style so that's another 700.

Here is a parts link for BAM, and they show prices but there not the least cost
http://www.mercruiserparts.com/bam/s...1941/16012/160

I would be leaning toward the stainless ones, but even they can rust out given enough time

Well, looks like $2500 or so is the best I can do either way. Thanks for the help.

Do you know if I need the expansion plugs? Doesn't look like they are anything I can get out of the old ones so I was hoping they are already pre-installed.