That nipple needs to be removed, screws out, while riding. Take the nipple to your local hardware store and buy a female quick connect fitting for garden hose. To flush, screw in the male quick connect, and connect the hose with female quick connect attached. Always start engine first, supply water, flush, turn off water, then shut off engine. Read the manual...
Yep, my phone sent this...
Yep, my phone sent this...