Manifold and risers when to replace/clean?

[rtmt91]

I have been reading different posts and such about manifolds and risers. Removing and cleaning, or replacing.
How often should it be done?
Can you check them without removal?
What are some of the issues.
What benifits do you get by replacing?
What benifits for cleaning them out?
How to clean?

I have a 1987 merc/260 alpha1 and this is my second year with the boat, I am not sure if the risers/manifold are original or not.

Is this someting I should look into? The temp seems to be fine. I can touch the top of the riser and it is warm, and the top of the manifold is a little warmer.

 

[Haut Medoc]

Re: Manifold and risers when to replace/clean?

Salt or fresh water?......
Standard cooling or closed cooling......
There is no way to inspect them from the outside.....
Generally, you get 5-7 depending on usage......
If it were me, I would replace them, then you know their condition....
​

 

[stevieray]

Re: Manifold and risers when to replace/clean?

Salt or fresh water?......
Standard cooling or closed cooling......
​

That makes all the difference. Been running mine (raw water cooled) in upper Chesapeake Bay water for 18 yrs with no problems.

 

[rtmt91]

Re: Manifold and risers when to replace/clean?

freshwater in land lakes
standard raw water cooling

 

[Haut Medoc]

Re: Manifold and risers when to replace/clean?

Well, IMO, if they are the original manifolds/risers, then I would replace them......
Even if they are used only in fresh water....
Stevieray getting 17 years out of a set of manifolds is the exception, not the norm.......
At best you could remove the risers & inspect how much of the mating surfaces are left....
If they fail & put water into your cylinders, you won't be happy.....
& I don't mean to sound all gloom & doom, it is your choice....​

 

[180shabah]

Re: Manifold and risers when to replace/clean?

A pair of gaskets is like 10 bucks, take'm apart and see what they look like.