i did a stupid thng today

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benlui

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left the mooring by sail in 30kts of wind,3 hours later when i ran the engine it didnt sound great,and after 5min smoke started coming from the exhaust so i ran below only to find a burning smell, i realised i had not turned on the engine sea cock when leaving. I did the routene 2 min start prior depature.
I emmediatly shut off the engine, and restarted 5min later with the sea cock on, and after a min of blowing smoke, she ran us home no bother. Could i have caused damage? It ran for 45min after no problems but I hope i didnt do damage. Its a nanni 21hp diesel inboard with under 200hrs.
What a silly mistake.
 
Should be ok, you might want to smell oil, incase its burned, and check the coolant if heat exchanger cooled incase it needs toping up, however you will definitely need to replace the raw water impellor, even if it looks ok i would change it because it will have been severely weakened. If any veins are missing, check through pipe work strainer ect for them, and in heat exchanger if there’s one fitted. Easy mistake to make, but i have 'check water from exhaust' in my starting checklist as well Matt
 
5 minutes is unlikely to have been long enough to get the engine above normal working temp so would not have expected any trouble with the oil or loss of coolant from an indirect system.

If the water pump was not actually dry then it may also have escaped damage but impeller replacement a wise precaution.

The hoses in the exhaust system are the most likely components to have suffered along with any plastic bodied water-traps, mufflers etc
 
Because I cannot rely on my memory, when I turn the seacock off I hang the engine key over the seacock lever to remind me to turn it on again before starting the engine.
 
If the seawater is cooling a heat exchanger then I'd think that 5 minutes was probably not enough to get the water jacket up to full temperature unless you were really loading the engine. The big risk would be the exhaust hose and the impeller itself. If the impeller was run dry and started to smoke the smoke would end up in the exhaust line and you'd see it as engine smoke.

Whip the cover off the pump and check the impeller. If it is knackered you might not notice the effect until you have to push the engine hard and its performance is reduced enough to not be able to cool the heat exchanger enough. Also it may be damaged in such a way that it could fail at any time.

I have a fitted a flow switch into the seawater line that works alongside the temperature and oil pressure alarms.
 
Re: i did a stupid thing today

Happens - hanging the ignition key over the seacock handle is a good way to prevent that.

Don't hesitate, replace all the engine exhaust hose and the raw-water impeller - they'll fail shortly and probably very inconveniently.

You'll find out soon enough if you've damaged the engine - difficult starting and loss of coolant (if indirectly cooled). If it's raw-water cooled I again wouldn't hesitate. Have off the head and into a machinist and take off 0.08mm, to reduce the possible distortion.
Seawater in the bore will shorten the engine life dramatically.
 
the fact that you had smoke (sure it wasnt steam?) shows that you damaged something. the puzzle is what. getting an engine hot enough to cause the oil to vapourise would normally lead to bearing failure so it cant be that. nothing electrical should be affected by the engine running without cooling seawater. the sea water impellor (which you definitely should now change) is inside a brass case so shouldnt smoke. so what was smoking?

did you not hear the overheat alarm?
 
Had a similar thing (smoke from engine exhaust) on a charter boat when the impeller failed. The smoke came from a damaged water lock and burnt exhaust hose.
I would check these as already recommended.
 
Parts of the engine that normally run cool due to seawater, will smoke if they have oil splashes or stains from maintenance procedures on them and are heated up -even just a little (exhaust manifold?). Don't panic !
 
Welcome to the club. In the past I had got into the bad habit of leaving the sea cock open when away from the boat. Now I am reformed and take the engine hatch off when leaving the boat to remind me about the sea cock. However, I must get a big notice to place on the chart table as I will not want to leave the hatch off when moored overnight and sleeping in the boat.
As it is confession time, how about antifouling over the water intake?
 
Ok thanks for the advise, better to be safe than sorry. The high temp warning alarm did sound, sorry i forgot the mention that. I have the engine supplyer fitting some new things on the boat, so i think ill get him to look over it also. Its a stupid mistake thats gona cost me some more money, and i only serviced the engine 4 weeks ago grrrrr. thanks again
 
It something many of us have done.

The clue is the sound of the engine, the exhaust sounds tinny...

When it happened to me the mixing box melted!

An odd place to put a plastic box!

I had to be towed in, as now the engine was unable to get rid of its cooling water. As for the engine, the smoke was probably oil that was on the outside of the engine, and as long as you switch it off when the heat alarm went off, it should be ok.
 
Don't panic and do anything too extreme..

Just start the engine and run it whilst moored. After its warmed up Put her into gear and run it for a while at about 3000 rpm for 5 or 10 mins.. Check if it overheats or starts to blow smoke.. If neither happens, then normally speaking you don't have a problem. You could, as the gentleman mentioned earlier, anyway inspect and if necessary change the impeller on the water pump as a precaution.
 
Is this a tradition, something everyone has to do once? I did it once, even more blatantly stupidly, since I started up on the mooring with no excuse to have missed the normal checks. Only ran for a few seconds before the hollow exhaust note alerted me and I dived below to open the cock.

Sounds like you sailed off the mooring, then first used the engine when at sea. I'm not at all sure I'd have noticed the engine note in those circumstances.
 
there's a strong possibility you'll get away with it. I did. Agree about the impellor though. If you switched off when the temperature alarm went off based on my expereince you should be alright. After all that's what the alarm is for.
 
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