Reverse flow out of my flush hose connector pipe on my 2003 Merc 115 hp 2 stroke ???

[desertislander]

Not quite sure whats happening here but it can't be normal. When I was fueling up today at Ocean Shores I noticed quite a bit of water back flow through the pipe I normally connect my fresh water hose to when flushing after a day out on the briney. I was reversing and moving forward at almost idle revs when it happened. I still had water squirting at a good rate from the hole on the cowling where it should come from during it's cooling cycle so I just figured it must be a kind of escape pressure valve. There is a plastic cap that sits over the end of this flush pipe when not in use but is only held on by a toggle, not threaded or bayoneted on so often gets blown off by this reverse water flow? This also happens when traveling at speed.

[Chimo]

You may avoid blocked water galleries if you flush your motor either with muffs or by using a barrel to flush your motor.

There is a body of opinion backed up by cups of salt etc dug out of disassembled engines that flushing with a hose while the engine is not running is not the most effective way to get salt etc out of all the engine galleries after a day on the bay.

Cheers
Chimo

[Fed]

Should be a check valve to stop any water coming back out.