Flushing a 4.2L Yamaha

[wlewis]

I believe Yamaha says when running the V6’s while flushing, 2 hoses are needed, one running through ear muffs and the other through the hose fitting.

 

[Doc Stressor]

Yep. Only with the hose adaptor. You can tilt the engine up when the boat is in saltwater and flush it with freshwater with the hose.

 

[Doc Stressor]

I believe Yamaha says when running the V6’s while flushing, 2 hoses are needed, one running through ear muffs and the other through the hose fitting.

I was told that also when if found that my F250 would overheat when running with the muffs. It wouldn't overheat at idle, but when I upped the revs for diagnostics I would get a buzzer after a while. After following the recommendation of a Yamaha service tech to use both the muffs and the hose, the problem went away.

 

[wahoo33417]

I'll ask a dangerous question. My Yammie dealer said to not run the engines when flushing. Just hook up the hose and let it flush, as long as there is strong flow out the pee hole, the water jacket should be getting what it needs?

 

[SkunkBoat]

Millions of boaters who are in the water all season shut it off, raise the motor, and flush with the hose port and don't worry about such things...unless they are on the hard and running the motor.
Seems to me you are overthinking it...KISS