1988 Mercury XR4 150 Poppet Valve Replacement Leaking via Weep Hole

[oavaughan]

I just installed a Poppet Valve kit on my Mercury 150 XR4 and when tested the water is jetting out the outer small hole on the Poppet Valve Casing /Cover. The install is very basic, but this situation has me stumped. I have searched the Internet but with little success. I have an old Service Manual, but it doesn't detail anything about the Poppet Valve. If anyone has experienced this before or has any suggestions, I would most grateful. Thanks a bunch.

 

[oavaughan]

I found the solution. It was a gasket issue. Apparently there are different sized (thickness) gaskets for the various different configurations of poppet valve installs of the Mercurys in this era. My 1988 XR4 requires basically paper thin gaskets to ensure the poppet diaphragm makes contact with the outer housing. Using thicker gaskets creates a gap. The gaskets I received in my kit were about 6X the thickness of the originals. How I found out was to create my own gaskets with similar thickness materials to test and the Poppet worked fine. Now, I am trying to order the correct thickness gaskets to finish it off.