F150 water leaking from base of exhaust cover

[artcumming76]

Yamaha F150 has a water leak annd appears to come from base of exhasut cover. This is the plate cover on the side of the powerhead that has the t-stat, rectifier, pressure control valve in it. Only noticed today after performing standard oil change, plugs etc when running after doing a check everything is good. Place fingers under this plate where gasket mates to powerhead and can feel water spray.
Anyone experienced this before?
Thanks,
Andrew