White Stuff In Water from Exhaust?

[cwarren]

When I start my engines (Chevy 305's I believe) I see what appear to be white bubbles/globules in the water near the exhaust. The float at the water's surface. I think it might be fuel, but it looks like milk. Any thoughts on what this might mean? I've seen it come from other boats before, but I'm sure there must be some bad news associated with it.

Chad

[SomeSailor]

Is it every time? Even after warming up, etc?

[cwarren]

I have only noticed it when the engines are cold.

[SomeSailor]

Sounds like unburnt fuel. Are your chokes opening OK? If they're stuck, you'll get a milky, smokey sort of white bubble scum back there. If you reach down into the water and get some on your hand you can smell the gas fumes.

How's it running otherwise?

[cwarren]

I think they run like champs (knock on wood). They start on the first try every time and run smoothly and they have about 1350 hours on them. Maybe I can get them adjusted along with a tune-up. I'm not very savvy in the engine work department.

[SomeSailor]

Probably just the chokes sticking a bit. Pretty simple work, but notying neats a good tune-up.

[Tedster]

Could also be a blown head gasket, is it useing coolant?

[Numbknots]

suggest that you pull the dipstick and see if the oil on the stick looks milky, if so definetly a head gasket, crack or some other problem that water is mixing with oil? Also have a look at the coolant recovery tank, if it is bubbling, another indicator that suggests a blown headgasket.

(all this said it could be as SS said just a sticky or improperly adjusted choke)

Tim

[SomeSailor]

Hopefully that's not the case, but as he says it on both motors, and they're both running well...

Reason I say this is I had the choke stick on my 2355 and it did the same. You can actually smell the fuel on the water as it's happening. It's like watching an old 2 stroke warm up :)

[cwarren]

Well, I'm going to go test it out tonight. I'm knocking on wood, crossing fingers, doing the dance, and anything else I can think of. I'm scheduled to depart for the San Juans on Friday (gulp) :|

[cwarren]

I tested this out last night. Let the engines warm up (didn't see the white bubbles/globules this time). After the engines warmed up I shut them down and check the dip sticks and the oil looked great.

I did notice the starboard engine put a bit of a gas slick on the surface of the water. Probably a carb adjustment I suspect.

CW

[SomeSailor]

Since you have twins. Remove the spark arrestors from them both and monitor them as they warm up. I bet you'll notice one of them holding with the choke closed longer than the other. Pretty easy fix really though.