Atomic 4 Steam?

[sailnoproblem]

I took my boat out for the last sail of the season yesterday. Under power there was a lot of white steam (vapor) coming from my exhaust. Also a bit of popping noise coming from the exhaust at low idle.(I have a scupper on my exhaust for added protection. I thought that the flapper was stuck or just not flexing due to the cool water. It was the cause for some of the popping but not all.)
Back at dock I checked my oil for water and it was clean, the plugs were clean, and the engine ran strong no misfire.
The humidity was high and a little low fog, but I doubt that was it.
It's an early model ATOMIC 4 which I rebuilt during the boat restoration 2 years ago. I think it may be the muffler as I did not replace it.
Any suggestions

 

[Sandy Stone]

Sounds like low cooling water flow to me. Check your raw water impeller, strainer, etc.

 

[Eddie7045]

Is it misfiring at low speed WHEN IN GEAR ?

.

 

[Barnacle Bill]

Steam can indicate that there is leakage in your head gasket so that water is getting into the cylinders and hence steam out the exhaust. Did you overheat the engine recently? If so, you could have blown the head gasket or warped the head so the seal is gone. That is the first thing I would address.

 

[sailnoproblem]

Re: Is it misfiring at low speed WHEN IN GEAR ?

She idles fine.

 

[west wind]

atomic 4

Past experience tells me you have a blockage, where the water hose comes out of top of the head and into the exhaust manifold, remove the hose from the top of the head, that hole tends to scale up from rust, poke it with a screw driver to clear it, that has happened twice in the past few years, good luck, can't hurt to try it....This was on my 1973 27ft Catalina..

 

[Benny17441]

It does sound like poor water flow.

 

[sailnoproblem]

I did a compression test and it's fine. Must be in the water flow.
Thanks

 

[Eddie7045]

The popping noise that you refer to when idling ? Is

that while in gear or in neutral or both ?

 

[RichH]

At the dock, engine in neutral, and running at ~2000 rpm ... measure the VOLUME of exhaust water coming out (use a bucket and a stopwatch).
• If the flow is at about 3 gallons per minute (@ 2000 rpm) youre probably fine and what youre seeing is water vapor condensation at the exhaust discharge due to the 'dew point' of the surround atmosphere .... high humidity, low ambient temp, hot/warm exhaust water.
• if less than 2-3 gallons per minute outflow at 2000 rpm, the check for worn raw water pump, restriction (slab rust) in the exhaust manifold, ...... if your boat has a jacketed COPPER exhaust section 'after' the exhaust manifold then test for leak between the 'gas side' and the 'raw water side' .... plus if if you have a copper 'steam riser' - a vertical COPPER 'steam pipe' (see attached) check to see that the 'witches hat' is still there inside the steam pipe'.

This time of year its usually the atmospheric 'dew point' being lower than the gases coming out of the exhaust ... and you see 'volumes' of what looks like steam (condensed water vapor, actually). If your engine temp gage is near normal, then its probably a 'dew point' issue at the exhaust outlet.

hope this helps.

 

[sailnoproblem]

Re: The popping noise that you refer to when idling ? Is

neutral.

 

[sailnoproblem]

You may be right about the atmosphere as one of my crew is a top notch mechanic and he said the same thing. There was a considerable amount of fog low.
But I want to check every scenario.
Best regards and fair winds.

 

[Bill Roosa]

Your car does the same thing on a cold morning except it has a really big engine (gets hotter) and a metal exhaust (transfers heat better so it does eventually get hot) and no water in the exhaust. My Catalina 30 used to do this all the time when the weather turned cool.
I'd not worry about it.