1978 mercury 70hp water leaking from spark plugs?

[Jsmall81]

So, I am in the process of basically rebuilding this motor. New sparks, spark wires, ignition coils and switch box and fuel lines. Finally went to start it up and it fired up! Super pumped. Now.... I noticed water coming from the spark plugs, pretty badly. What is the cause and fix? Thanks!

Here's a video https://streamable.com/vaekas

 

[racerone]

Remove water jacket cover.----Replace the gasket.

 

[Chris1956]

Or dry out the area and put some silicone over the leak.

Those mangy 1/4-20 water jacket screws tend to break when you try to remove them.