white spots from exhaust

[sailingis.fun]

Apologies if this has been addressed elsewhere but couldn't find a better place. Does anybody have any idea what this could be? I have asked several mechanics and nobody can figure it out. I have a Volvo Penta and just this year, my exhaust started putting out some sort of white stuff in the water. It sort of looks like maybe its unburned fuel. It presents its self like oil in its pattern but it doesn't have a rainbow effect and its more of a milky/cloudy white. No other color to it. Sort of bubbles up and spreads.

I would think it was maybe fouled plugs or something that would cause unburned fuel to be expelled but the engine is running absolutely great. Oil is not burning off and at a consistent level. Steering fluid (which we did have problems with for a few years) has been fixed and staying at a consistent level as well. We do get our engine winterized every year and this started from the first start of the season and has been happening ever since. I have tried running it off, replaced fuel, high RPMS to burn... nothing seems to get rid of it. Sometimes it is worse than other times too, can't seem to find an answer. It is most likely from the exhaust too because it bubbles up. Like, it isn't dropping onto the water but bubbling up from underneath. It is hard to capture in a picture but I attached one and circled some of the spots you can hopefully see. Any direction to head towards would be greatly appreciated.

[ItDepends]

Sure looks like fuel to me….

Try collecting your exhaust water in a bucket and get a closer look. If it is raw diesel, you nose will know.

[Rumrace]

Check your anti siphon valve. It looks like water in the engine.
Don’t run the motor until you confirm I’m wrong.

[DougR]

How about a fouled plug from fogging the engine during winterization?

Pull the plugs and see what they look like.

[Bill O]

What "plugs" (spark), aren't we discussing a diesel motor?

[DougR]

Originally Posted by Bill O

What "plugs" (spark), aren't we discussing a diesel motor?

The OP doesn’t mention the word “diesel” at all, and he makes reference to fouled plugs.......

[Bill O]

Yes, you are correct they didn't mention diesel, but did mention Volvo Penta. While they did make OBs (now vintage) and some newer 4 stroke OBs, the majority of the VP marine line are diesels.
It would be nice for the OP to clarify if the white spots are from an old 2 stroke OB or from an inboard. Makes a big difference to help make recommendations between the possibly 2 different types of motors.

[DougR]

Originally Posted by Bill O

Yes, you are correct they didn't mention diesel, but did mention Volvo Penta. While they did make OBs (now vintage) and some newer 4 stroke OBs, the majority of the VP marine line are diesels.
It would be nice for the OP to clarify if the white spots are from an old 2 stroke OB or from an inboard. Makes a big difference to help make recommendations between the possibly 2 different types of motors.

I agree, the OP could have been more forthcoming with info on the engine type that he has. That said, it’s also helpful to know that VP is still one of the larger players in the gasoline stern drive marine business. In the heyday of the gas sterndrive business, not too long past, VP produced as many as 22 or 23,000 gasoline sterndrive units per year at their Lexington, TN factory. Most of these were sold in N America, but plenty exported as well. Way more than they ever sold per year of marine diesel engines in N America.

[sailingis.fun]

Thank you so much for the replies. I love this community and I can't believe it took me so long to pose the question here.

Yes, the Volvo Penta is Gasoline, not Diesel. Inboard. Not sure why the picture is upside down, but if you stand on your head you get the idea. lol

As for fouled plugs... wouldn't my engine be skipping or running rough if that were the cause? I mean it does make sense to me, just thought it would be a bit more obvious if it were the plug issue.

Thanks again!

[sailingis.fun]

Originally Posted by Rumrace

Check your anti siphon valve. It looks like water in the engine.
Don’t run the motor until you confirm I’m wrong.

Did check the valve. Holds pressure fine and as it turns out, was replaced less than 2 years ago.

[Sailmonkey]

Have you checked the fuel pressure?

If the fuel pressure is too high, the pwm timing of the fuel injectors allows more fuel into the cylinders than is required, hence the engine runs rich and will smell rich as well as leaving fuel on the water.

There should be a Schrader valve on one of the fuel rails to measure the pressure.

[sailingis.fun]

Originally Posted by Sailmonkey

Have you checked the fuel pressure?

If the fuel pressure is too high, the pwm timing of the fuel injectors allows more fuel into the cylinders than is required, hence the engine runs rich and will smell rich as well as leaving fuel on the water.

There should be a Schrader valve on one of the fuel rails to measure the pressure.

Thank you. I'll check for it.