Engine alarm sounded but can,t tell what caused it.

Contest1

Contest1

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Out yesterday, beautiful warm steady force 3 day here in Dublin.
Was motoring into the wind to get the main down when the alarm came on.
Same sound as key start before engine kicks in.
Killed engine but alarm kept sounding untill keyed off.
Started engine several times but alarm still on as engine ran.
Was on my knees looking at the 3 start pannel lights, 2 off, and middle one was on. The symbol looke a bit like a water level, horizontal line mid way up a rounded u shape.
While fiddling around with the key switch the alarm stopped, and the engine ran ok on the return to harbour.
I had tried a forum tip re my eratic sounder, ie turned the key switch off while engine running some time earlier but this had no effect on the sounder and the alarm didn,t sound then.
Pals on the harbour suggested my cooling water exhaust flow looks retarded but the waters only warm to the touch at idle and I can keep my hand in it at higher revs. The volume increases as the revs increase.
Any thoughts?
 
which warning lights didnt light? The problem can only be oil pressure or leccy or water temperature. On that basis it should be easy to work out which.

Assuming you are right then the problem could be one of three- faulty sensor, faulty wiring or a hot engine. Doesnt sound like the latter from your description. More like duff wiring
 
On Volvo the 'big C' symbol with wavy line in the centre is the Glow Plug 'on' sign which should not sound the alarm. Could be you sucked a Jelly Fish or weed into the water intake to obstruct water flow, the engine overheated. When you stopped the engine, the obstruction washed off permitting water flow again but alarm continues to sound because the engine is still too hot. Engine cools and alarm goes off. You restart engine and water flow is fine because the obstruction has gone. Perhaps some damage to impeller while running dry briefly so check. I've had this happen once with a Jelly Fish - which ended up in the bilge under the engine (prompting a useful 'how do you get a Jelly fish out from under the engine post') and the second and third times with weed. Why no warning light - perhaps the bulb has gone - check again.

Accept this is speculative but there are a couple of things to check out.
 
Thanks for the ideas.
Worked on the water side this morning.
Eventualy found the thermostat calcified in the almost closed position.
Freed up and checked the operation with hot water, seems ok now. Probably not letting the main flow out of the block thus overheating before mixing with the cold bypass water..
Will check under load when the tides in tomorrow.
 
Just ba k from the Isle of Mann.
Light winds so motor sailed both ways.
Still concerned about cooling water flow but no further alarms, TG.
Checked every thing before starting off, even put some hdracloric acid into the engine block via the anti syphon exit hose , then ran it out after an hour.
Lots of bubbling back up the hose and a milky colour at the exhaust.
No great difference to the water flow, and still lots of steam when she warms up.
Removed the thermostat for the return leg, no real difference.
The harbour lads are devided, if its not broke or strip it down.,
The water leaving the block seems cool enough through the anti syphon valve, into the exhaust manifold.
:confused:
 
I have separate senders for the gauge and the alarm, so if a sender is faulty it may sound the alarm while the gauge shows no problem. Or vice versa.
 
If you had calcification on the thermostat the chances are you will also have some in your elbow. It may be that this is restricted or blocked causing the engine to overheat.
Got a friend here with an overheating engine and little cooling water coming out. When he stripped his elbow it was almost totally blocked. He cleaned it out and now has no problems and the engine runs a lot cooler.

Does anyone else ever use Hydrochloric acid in the engine to try and clean it out?
 
Nostrodamus said:
If you had calcification on the thermostat the chances are you will also have some in your elbow. It may be that this is restricted or blocked causing the engine to overheat.
Got a friend here with an overheating engine and little cooling water coming out. When he stripped his elbow it was almost totally blocked. He cleaned it out and now has no problems and the engine runs a lot cooler.

Does anyone else ever use Hydrochloric acid in the engine to try and clean it out?
Click to expand...

I'll be interested in the answer to this one. It's not something I would ever do.
 
I've had that a few times with my raw water cooled 1GM10 when sailing with the engine on or motoring in lumpy conditions.
I've come to the conclusion that air is taken into the cooling water resulting in an airlock in the impeller and so it overheats. Dropping the revs and getting upright is usually enough to get things moving as they should. If the alarm continues for more than a few more seconds I kill the engine, give it a few minutes to cool, then all is back to normal.
 
A1Sailor said:
I'd be interested to know what the resultant milky stuff was...
Click to expand...

I assumed the acid, recomended by the local trawlermen but with the stat out and introduced as described to protect the impeller, disolved some calcium scale.
Going to check the mixing elbow as soon as I break into the boat, key locked inside :rolleyes: Foolishly took it of the bunch when the crew, son, mutinied after he got fed up at the old codgers get together when we got back from a very quiet Douglas on the mad Sunday that wasn,t.:mad:
 
No mixing elbow but a very slight off set mixing bend at the end of the exhaust manifold.
Treated the exhaust to a direct injection on hydracloric acid, seemed to improve the manifold cooling dramaticly.
Hope to test it out this weekend, weather Gods permiting, on a cruise to Carlingford.
 
Just an aside: my Nanni set off the alarm when motor-sailing in similar conditions. Too bright to see the lamps, but I believe it was low oil pressure due to the heeling. Killed motor for five minutes as clearly didn't really need it then restarted after dropping sails with no alarm.
 
Nostrodamus said:
Does anyone else ever use Hydrochloric acid in the engine to try and clean it out?
Click to expand...
Tony Cross said:
I'll be interested in the answer to this one. It's not something I would ever do.
Click to expand...
Nostrodamus said:
It worried me a little but Centeur 1 seems to have done it.
Click to expand...
A1Sailor said:
I'd be interested to know what the resultant milky stuff was...
Click to expand...
HCl is a little on the strong side for my taste. I have used Phosphoric acid (H3PO4) with great success diluted to around 4% w/w which it turned out was a little more than required - a 2% soln would have sufficed.
 
Still lots of steam, took off the mixing bend.
The acid cleaned up the cooling ways ok but couldn,t reach the inner cooling face of the mixing bend.
Job done:D
Steaming on Carlingford lough, catching the early ebb.
 
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