Mercury F225 water leak?

[HawaiianHooker]

2004 Mercury (Yamaha) outboard F225 seems to leak saltwater from the top Starboard side. I only use it in salt, flush with saltaway every time but when I later pull the cover off I have dried salt mostly from the top and Starboard side. I've cleaned it off and it reappears. Tried finding it while on the water just high idle but dont see anything. Possible splashing into my cover or leaking from somewhere? Mystery for sure..

 

[boscoe99]

Remove the thermostat. Inspect the interior and exterior of the thermostat housing. Housing being an integral cast part of the block.

 

[boscoe99]

How many hours are on the motor?