Should i get new risers/manifolds pics inside merc 7.4

[jake1z]

boats a 96 century with the 300hp 7.4... They look a little beat up, would they make it through this season?

 

[Bondo]

Re: Should i get new risers/manifolds pics inside merc 7.4

Ayuh,... Looks like ya barely caught it...

Clean 'em up with a flat file, 'n see if they've got another lap in 'em...

 

[Don S]

Re: Should i get new risers/manifolds pics inside merc 7.4

What you need to do is clean the gasket surfaces down to shiny metal. The webs between the exhaust and water pasages should be around a 1/4" wide of bright shiny metal.
If, in your middle picture that web between the exhaust and water passages is down to clean metal and it drops down like that, they are junk. You need new manifolds and risers. Replace as a set.

 

[bloodyknuckletech]

Re: Should i get new risers/manifolds pics inside merc 7.4

Also once clean check for "pitting" on the sealing face for the gaskets. If there's tiny holes everywhere is recommend new. And the rust starting on the internals of the manifold is not a good sign