What is this 'Wash' screw for?

[Herman Melville]

Can I attach a screw thread and hose to it and flush the engine?

Right now I use mufflers - this would be much better if that was possible.

​​​​​​​Cheers

[chipko]

Probably a water plug for a flushing attachment.

Our Tohatsu 9.8 has one.

[Bournemouthroyal]

Using muffs with the engine running is the best way for flushing your engine. Using a flush port is a good alternative, but doesn’t get clean water into the pump.

[GARYSHORT]

Some engines/motors CANNOT be run if you are using the wash screw as water does not circulate around the impeller. Check your manual.