(DO NOT REMOVE) Cobra permanent water upper case plug solution.
Simple solid plastic plug designed to be installed without removing
your sterndrive. If you are interested in this offer, you, most likely
opened a Pandora Box on the upper part of your Cobra sterndrive. The
original, so-called (removable version) is pictured here and priced at
$75 for the set and will require access to the back of the
sterndrive's water passage to secure the metal wedge.
My personal Experience
Just like everyone else I opened the water passage plug. I did not
have a luxury of removing my drive and had to create a reasonable
solution to close the gaping hole in the drive. I went to the store
and picked up rubber plug which sealed this hole tight. Little did I
know after taking my boat on to the open water any engine speed above
2500 RPM turned to a rapid overheating. My engines and risers are all
new and work very well. The issue at hand was the narrow water passage
in the drive, interrupted by the depth of the rubber plug. I had to go
back to OEM calculated plug.
In this offer 9xmarine offers solid, 3D printed permanent threaded
plug which needs to be install using silicone or JB Weld. JB Weld is
preferred. See provided instructions