Lots of white smoke out of exhaust!

[SailingReckless]

Engine is starting up great and staying running without stalling out now after I replaced a bad ignition coil this morning! Hurray
So much white smoke out of the exhaust though I let it run for about 5 minutes or so and the smoke didn't let up. I don't have a working temperature gauge yet so I was worried that maybe it was overheating and shut it down.

I read other threads relating to this but nothing clicked or made sense to me.
What is the cause of the white smoke? Or are there multiple things that could cause it? Is there a way for me to tell if it's steam or exhaust fumes?

My next job will be to get the temperature gauge working.


Can anyone help me out with how to test those fittings? There is also temperature gauge connected that is getting power but not reading. The pressure gauge is working. I cleaned up a couple of the connections but still nothing. Really don't want to buy the new parts until I know for sure that what I have is bad.

[lat 64]

Smoke will smell bad. White smoke would most likely be oil burning. Black smoke may be a too-rich fuel mixture or choke on. Water vapor from combustion can be seen if the air temp is cool enough but it will soon dissapate(disapear) after a few feet away from the exhaust. Steam may look like combustion water vapor but lots of it may indicate a water leak into cylinders.

Can you post a youtube video showing the exhaust as the engine runs?

[ndutton]

As soon as we know if it's steam or oil smoke we'll be able to help. BTW, the second picture clearly shows the oil pressure and temperature alarm I mentioned earlier. The little black box is the buzzer. It should make noise every time you start the engine. Once it's running the buzzing stops. The temperature sensor with the white wires is a temperature switch for the alarm system. There is a similar oil pressure sensor/switch at the other end of the white wire. If the buzzer is not buzzing, there's something else to fix.

[JOHN COOKSON]

To test the temp gauge:
Disconnect the wire from the sending unit at the gauge then power up the gauge. It should peg low.
Then short the gauge sending unit terminal to ground. The gauge should peg max.
Remember the coil will be powered up when the key is on.

TRUE GRIT

[ndutton]

Remember the coil will be powered up when the key is on.

For the safety of the new coil, disconnect it during the test. You connected it, you can disconnect it just as easily. Tape the wire ends so they don't accidentally touch anything they shouldn't.

Protect the coil!

[SailingReckless]

Smoke will smell bad. White smoke would most likely be oil burning. Black smoke may be a too-rich fuel mixture or choke on. Water vapor from combustion can be seen if the air temp is cool enough but it will soon dissapate(disapear) after a few feet away from the exhaust. Steam may look like combustion water vapor but lots of it may indicate a water leak into cylinders.

Can you post a youtube video showing the exhaust as the engine runs?

Leaving the boat this morning but when I come back in a few days I will post a video. If there was water in the cylinders would that make the oil cloudy or milky? The oil now is very clean and clear. I had Marvels Oil in the cylinders over winter. Could it be that still burning off? The air temp was in the mid 60s yesterday and it was dissipating quickly but it was ALOT of white smoke. You’ll need to see the video. I’ll post asap.

[SailingReckless]

As soon as we know if it's steam or oil smoke we'll be able to help. BTW, the second picture clearly shows the oil pressure and temperature alarm I mentioned earlier. The little black box is the buzzer. It should make noise every time you start the engine. Once it's running the buzzing stops. The temperature sensor with the white wires is a temperature switch for the alarm system. There is a similar oil pressure sensor/switch at the other end of the white wire. If the buzzer is not buzzing, there's something else to fix.

The buzzer is buzzing! Is it safe to say that if the buzzer is buzzing upon start that it will also buzz if temp gets too high?( I think I read over 200)? The oil pressure gauge at the other end is working. My plan is to try a new temperature gauge first to see what happens. I tried cleaning up all the connections to the old one and it still didn’t read anything. I did notice that the back of it was getting pretty hot so hopefully that part is just bad.

[ndutton]

Don't quote me but if memory serves the temperature threshold for the alarm system is 240°.

John Cookson's test will tell you if you have a sender or gauge problem, perhaps indicate a wiring problem too. We usually advocate testing first to avoid changing parts that are good, aka parts therapy.

[lat 64]

Leaving the boat this morning but when I come back in a few days I will post a video. If there was water in the cylinders would that make the oil cloudy or milky? The oil now is very clean and clear. I had Marvels Oil in the cylinders over winter. Could it be that still burning off? The air temp was in the mid 60s yesterday and it was dissipating quickly but it was ALOT of white smoke. You’ll need to see the video. I’ll post asap.

Clear oil: GOOD!
Lots of white smoke that dissipates: probably water. We will do the twenty questions thing to zero-in on the source. It may be downstream from the water injection in the exhaust but I don't have that kind of wet exhaust so other forum members will be better resource for figuring that.
The recent head gasket work is a point to look at in case the excess vapor started then. But, correlation is not nessesarily causation. I love Neil's term "Parts Therapy". It describes the way so many mechanics work on an engine, just hoping they hit on the right thing. Must gather good damning evidence before condemning a part.

[ndutton]

I love Neil's term "Parts Therapy". It describes the way so many mechanics work on an engine, just hoping they hit on the right thing.

Full disclosure: it's not my term. The credit belongs to our host. It does ring true though, doesn't it?

[Sam]

At the end of each season when I arrive at the boat yard dock I change the oil and "fog" the engine - spray a fair amount of fogging oil through the carb. While I am spraying I am revving the engine somewhat for a bit to keep it from dying out. A great deal of white exhaust smoke is produced. My thinking is the MMO that was added to the cylinders [similar to light fogging oil] is really what could be producing the smoke. Let it run a bit and see if it goes away.

[SailingReckless]

[YOUTUBE]junk2MBzWa8[/YOUTUBE][YOUTUBE]https://youtu.be/junk2MBzWa8[/YOUTUBE]



Here’s the white smoke from the exhaust. Have not had the time to check the temperature gauge yet. Hopefully this weekend😊

[ndutton]

Not smoke, that's steam. The volume suggests water is getting where it shouldn't. I recommend a couple of cooling system pressure tests: the block and especially the manifold.

http://www.moyermarineforum.com/forums/showthread.php?t=11111

Please forgive my laziness for not rereading everything, is your engine raw water cooled?

[SailingReckless]

Not smoke, that's steam. It suggests water is getting where it shouldn't. I recommend a couple of cooling system pressure tests: the block and especially the manifold.

http://www.moyermarineforum.com/forums/showthread.php?t=11111

Please forgive my laziness for not rereading everything, is your engine raw water cooled?

YES raw water cooled

[lat 64]

I agree w Neil, steam. Well, water vapor anyway.

Have to leave you in his care as I don't have much experience with wet exhausts.
Re: pressure test, don't be intimidated by that. Its similar in theory to testing a bicycle tire for a puncture. You plug the big openings and put air to the system and listen for leaks hissing. Soapy water to show small leaks. And, perhaps a test pressure guage to show leakdown over a few minutes too.
I did it many times to engine heads in a shop but never did it to a seawater-cooled engine still in the boat.

Thanks for video, it helps.
R.