Gasket, riser, manifold

[sebas54]

Hi. How can you tell if the gaskets, risers, and maifolds are bad? I think that I may have a bad gasket but cant tell. Thanks

 

[MercMonster]

Re: Gasket, riser, manifold

What's leading you to believe that you think you have a bad gasket? Most likely in that area there would be water in the cylinders. You could pull your spark plugs and check for water or rust in the cylinders. Other than more available information, who knows?

 

[Don S]

Re: Gasket, riser, manifold

You can't check a gasket, if you take it apart, it gets a new one.
The risers can be taken off and inspected and the gasket surfaces can be checked for flatness and thickness. The passages can also be plugged up which is an indication of the insides of the manifolds and risers corroding away.
Note the areas marked in red in the pic below. Be sure they are shiny metal, and not the black carbon based material that can be scraped away.

 

[sebas54]

Re: Gasket, riser, manifold

Thnks for te info. I will check that later. What if they are black and not shiny Does this mean they are bad? Also I did find some water/moister on three spark plug on one side of th engine. No water came out when I pulled the plugs. Could this be becuse I have a bd rise/man and or gaskets? 1987 4.3L merc. THANKS THis website is great.

 

[Don S]

Re: Gasket, riser, manifold

What if they are black and not shiny Does this mean they are bad?

Yep, just waitin' to kill your engine.

Also I did find some water/moister on three spark plug on one side of th engine.

Probably time for new manifolds and risers "BOTH SIDES"
How old is your engine? Are they the originals? Do you boat in salt or brackish water?

 

[sebas54]

Re: Gasket, riser, manifold

My engine sfom 1987. I am petty sure that they are not th original. Maybe 2. 3. or 4 years old??? Fist year with this boat. First boat. The boat stays in salt water and is only used in salt water. How long do rise/mani last?

 

[Haut Medoc]

Re: Gasket, riser, manifold

2-3 years if you don't flush with fresh water after each use.....​