The pump area looks super clean, good job. Yes, that is for a garden hose, its to flush your engines cooling system. 2 minutes is a little long though, your carbon seal won't cool when its running out of the water. That fitting is only to flush your system, not for running them out of the water. 1 minute max on the hose, 15 seconds running max without the hose. I know you probably already know this but i feel obligated to say it anyways. Start engine, start water, shut water off, shut engine off. The garden hose should never be on when the engine is off.