Block-off Plate/Gasket

[FreeBeeTony]

I know Mercruiser came up with a new gasket that does not require the block-off plate.

​I have used them the past 2 times I replaced my risers and seemed like the gaskets were always questionable when I removed the riser from the manifold.
​I had a cooling leak at the end of last season that I really Haven't found, H/E seems to check-out, found a questionable hose.

​My thought this year is to remove the risers, clean the surfaces and install the old-style SS block-off plates and gaskets. Still thinking of using the new style gaskets for further protection.

Any thoughts/comments on my plan?

 

[alldodge]

No first hand knowledge but my opinion is I don't see the new style working. Reason being is there are slotted holes where the gasket needs to seal, and the gasket surface does not go out far enough to the edge

 

[Bt Doctur]

If I`m seeing it right you want to use dry joint gaskets for the block off`s? The wellcraft I take care of is FWC and I use the SS plate and 2 regular merc gaskets on the elbow/riser joint

 

[FreeBeeTony]

Just to be clear, I am not using the dry joint gaskets.
​Mercruiser cam up w/ a new gasket for the non-dry joint riser/manifold.

​I am suggesting using the SS Plate w/ 2 of the new gaskets (not the dry-joint gasket).

 

[Bt Doctur]

ok, That what I still use, Dont see any advantage to the composite block off gasket Mercruiser should look into the KISS idea. The SS plate and 2 gaskets works just fine, and aviation sealant just for some insurance

 

[FreeBeeTony]

@BT......so you don't think the "new" composite gaskets are necessary?
​Just to be safe. What re the P/N's you use for the block-off plate and gaskets?
​Any permatex replacement for the aviation sealant?

 

[Bt Doctur]

I use the standard 4 inch center riser gaskets .,either 4 open slots (27-860232 )or 2 open and 2 pinhole(27-863724) with the SS plate. Never a issue.. Permatex Aviation is a liquid sealant

 

[FreeBeeTony]

I use the standard 4 inch center riser gaskets .,either 4 open slots (27-860232 )or 2 open and 2 pinhole(27-863724) with the SS plate. Never a issue.. Permatex Aviation is a liquid sealant

Why not use the solid gaskets w/ the block-off plate?

 

[Bt Doctur]

You need 2 gaskets, one above and one below when using the SS plate. the block off gasket can only be used in that one application, the standard gaskets can be used for most applications.