New Yamaha 300 condensation from exhaust.

[Miker1234]

Hey all!

I have a new Yamaha 300 on my 2320 with 8.5 hours on it. I noticed there is slight condensation coming out of the exhaust at idle. It’s not smoke and doesn’t smell like burnt oil. I shot a video and showed it to my dealer and a certified Yamaha dealer and they said it’s nothing to worry about as long as there is water exiting the motor, it’s not overheating, and no error codes are popping up. The motor runs great. It was pretty humid the day I took the boat out when I shot this video. I did fuel stabilizer when I filled the tank half way.
Is this normal? Any advise is appreciated.
Thanks!

 

[Miker1234]

Just another note:
I also noticed it from day one during the test drive and I flush the motor with salt away after each trip.

 

[knotflying]

From my perspective this is normal and mine does the same thing. It usually happens more when the engine is cold. Our engines are water cooled and I assume similar to water cooled inboards. The cooling water blows out the exhaust. Most water will go out the prop exhaust, but I think there is always excess vapor that comes out via the exhaust silencer. Perhaps someone with better knowledge can add more info to this.

 

[Miker1234]

From my perspective this is normal and mine does the same thing. It usually happens more when the engine is cold. Our engines are water cooled and I assume similar to water cooled inboards. The cooling water blows out the exhaust. Most water will go out the prop exhaust, but I think there is always excess vapor that comes out via the exhaust silencer. Perhaps someone with better knowledge can add more info to this.

Thank you so much for the input. It’s been on the back of my mind for a while and I was just never sure if it’s normal or not.

 

[Brent]

Sounds normal

https://boattest.com/view-news/5768_why-does-the-outboard-coolant-stream-sometimes-steam

 

[Miker1234]

Sounds normal

https://boattest.com/view-news/5768_why-does-the-outboard-coolant-stream-sometimes-steam

Thank you for the link!

 

[Antidote]

It has noting to do with the cooling water. In a perfect burn one gallon of gasoline converts to energy and almost one gallon of water. We know or marine engines not close to a perfect burn; but, they do still make water. All those hydro carbons combining with oxygen = heat and water. On a humid or cold day you will see that water in your exhaust. It's normal.

 

[Cman60]

Btw the yami 300 does not spit water in a hard stream either like other engines I have owned but that does not indicate a problem as long as engine temp is good

 

[knotflying]

I noticed a rather weak stream on my engine, but figured as long at temperature was okay I was golden.

 

[djam]

My 2017 300 does exactly the same on both the vapor and the stream (I have about 960 hours on it with no issues). One thing to note as you are in the break in. A friend had the same boat/engine as mine/yours and treated it with kit gloves and had never ending issues making oil. I ran to the edge and slightly above during breakin and never had an issue. Yamaha told him these engines are made to be run. This is not advice on how to break in your motor, only what I know from my experience and the experience of others.