White steam coming from exhaust

[Craig Edwards]

I have a 2000 38 Sundancer and with 8.1 Horizon engines. There is steam coming from the port engine exhaust. Impellers were replaced last summer and a friend told me the steam could be due to a blockage somewhere in the cooling system. Any ideas on what causes this?

 

[mnm99]

Normal. Mine does it all season , more when the water is cold. New manifolds ect...is your water pressure good, are your temps good? do a search. Every 8.1 I know does it. Enjoy and don’t worry.

 

[sbw1]

I have never owned an inboard boat that did not have steam in the exhaust. It is particularly noticeable in the springtime when Lake Michigan is around 45-50 degrees F. The angle of the sun in the spring may make it more noticeable as well.

 

[hottoddie]

As long as your engine temp are normal at higher throttle settings do not worry. My 454s produce steam all year long even when the water is in the 70s.

 

[superwa]

Love my white steam. Tells me all is good!

 

[Craig Edwards]

Thanks for the feedback everyone. Much appreciated.

 

[scoflaw]

Well if it never steamed before and now it does, your buddy has a point.

 

[Great Lakes]

I have a 2000 38 Sundancer and with 8.1 Horizon engines. There is steam coming from the port engine exhaust. Impellers were replaced last summer and a friend told me the steam could be due to a blockage somewhere in the cooling system. Any ideas on what causes this?

I would investigate SB. Steam is completely normal from 496's

 

[Third Edition]

I had steam in the starboard engine and not the port -- 8.1L Horizons. Temperatures were normal. Mechanic put a camera probe in the cylinders and saw a bit of water on the sides. Expensive fix even though it was caught early.

 

[scoflaw]

Exactly my point, if it's so normal why only 1 engine?
I had a similar experience. Bought a used boat with the 502, steamed after a long run. Put on new exhaust and the steam stopped.

 

[juggernaut1]

OK on my 8.1s I've just put brand new seawater pumps, ex manifolds, stainless steel riser/elbows, ex manifold water drains, wet exhaust hoses, all intake hoses up to the seawater water pumps and Rydlyme'd the cooling system.........and both of mine steam. They also always have.

It's also more pronounced now as air and water temps are getting cooler from the land down under as we head towards winter.

I'd be more concerned about your starboard motor.

 

[Jimmy Buoy]

My 8.1's have always produced steam. It also consistently produces more steam from the Port engine but both read the same temps (even with the IR Temp gun). When I bought the boat 12yrs ago I replaced all the manifolds and pumps. It steamed then and hasn't changed since. Even Sea Ray's brochure for my boat shows steam coming from both exhaust ports - that was a brand new boat!

 

[370Dancer]

I think a better questions would be, "Why do marine engines produce steam in the exhaust?", and "Will an engine produce steam in the exhaust regardless of whether the majority of exhaust exits in underwater exhaust ports, or all comes out the sides/back?".
My personal experience has been that it's usually a telltale that the raw water pump needs attention. But, I'm just a shade tree hack. Perhaps if we knew why, then we could address/ignore based on our own situations.

 

[CaptRonn]

Exhaust=heat, mixed with H2O, the byproduct is steam.

Not sure why this is difficult.

 

[scoflaw]

Seeing that not all boats steam, probably has to do with exhaust gas temperature and the volume of water that it mixes with.

 

[370Dancer]

We're getting closer. Not all boats steam, and some do, but either all the time, or some of the time. And, even better, sometimes its one engine, and sometimes it's both. Yesterday, Starboard engine was steaming, but Port wasn't. I recently changed the raw water pump in its entirety on the Port. I am staging to do the Starboard. So, I'm interested in a more detailed explanation of what is going on, and what to look for, and why it might happen at all, so we aren't just throwing parts at it. About the only constants I can think of are incoming water temperature, ambient intake air temp in the engine room, ambient humidity in the intake air. Everything else is a variable. Especially if we are talking about 2 engines.

 

[mnm99]

Maybe the design of 8.1 elbows. The way the water is plumbed and the amount of heat in the manifolds. Okay , I don't know..lol. My boat is going in Saturday, and I can tell you when I go for my first run I won't be able to see behind me. The water is in the low 50's.

 

[melida]

I have a 2000 38 Sundancer and with 8.1 Horizon engines. There is steam coming from the port engine exhaust. Impellers were replaced last summer and a friend told me the steam could be due to a blockage somewhere in the cooling system. Any ideas on what causes this?

I have never been an owner of a gas powered boat except my 2.5 hp tohatsu so I'm not familiar with gas engines, so my comment will be general.

My diesels also started to create steam last season even I changed the impellers at the begining of the season there was blockage in the heat exchangers, so I acid cleaned them and steam gone.

So yours maybe a similar situation unless your engine/exhaust etc configured like that.

 

[West32]

Normal - Watch my Signature Video!