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As far as i can remember, when i used my engine last year i had a continuous flow of engine cooling water discharging via the exhaust into the sea. This year however although cooling water is discharged via the exhaust it is not continuous, but flow of water is interupted for 30 seconds between each burst of water. I have checked the impellor and the strainer, but am at a loss to see what might be the cause of the interupted flow of water exiting the boat via the exhaust. My main concern is that the engine may overheat if engine run at 2500 revs for long periods, and as sailing to Spain in June need to prevent this happening, so if anybody has any thoughts on the problem i would be very gratefull…….Ed Holmes Storm dragon
Are you sure about the continuous flow? Mine is in short bursts at lower revs but can get to nearly continuous at higher revs. If yours is 30 seconds between bursts and at higher revs then you may have a problem, but I wouldn’t know the answer.
Regards
John
LoblollyHi Ed
I think you will find that most boats discharge their exhaust water in spurts – certainly at low revs. This happens because of the swan neck in the exhaust hose. The exhaust gases can only ‘pump’ the water up the hill when sufficient collects at the bottom. At higher revs, with a higher flow rate of cooling water, this happens more frequently and may appear almost continuous.
That said, 30 seconds does sound like a long time. Mine glugs every 10 seconds or so on tickover.
Best of luck with your Spanish trip – keep the mast up this time! We are heading for La Rochelle (all being well) a week or so behind you.
Roger
Hi Roger, I am definately getting less water out of the exhaust at high revs, in fact at 2500 revs i make STEAM, but at tick over I get allmost a continuose stream of water, which makes me wonder if there could be a problem with the seawater pump, but how do you go about checking the flow, or is it a case of replace the pump and see if things improve. Ed Holmes
Ed
Unless the water pump has been off the boat, there is very little that can go wrong, apart from the impeller, which I understand you have checked/replaced so is not a suspect.
The only other suggestion I have is the anti-syphon valve. This should be airtight when the pump is pulling water. However, they occasionally get stuck partially open, generally with salt crystals, and this will restrict the flow of water, particularly when the pump is pulling hard.
It is simple to cure – a quick wash of the valve in clean fresh water is all that is required.
If this isn’t the answer, and you’ve checked all the other obvious restrictions to the flow (blocked inlet pipe, impeller etc), then I am at a loss.
I guess your last resort is a chat to your local friendly Volvo agent!
Good luck
Roger
Hi roger, many thanks or your assistance, After talking to a local volvo agent and removing the exhaust manifold, which he thought might be blocked at the point where the seawater re-enters the exhaust, and all to no avail, I then connected a hose to the seawater pump and put the other end into a bucket of water to check in case I had a blockage in the saildrive, but fortunately I still had a problem, but now knew the problem was between the seawater pump and the exhaust outlet, so starting at the seawater pump I replaced the impellor, which proved to be the problem, even though was a new one this year. The volvo agent thought that the rubber in the blades were probably a little soft and were not keeping contact with the metal at high speed, therefore reducing the water flow, unfortunately as not having the receipt he was unable to offer a free replacement, but the new one was only £21, and has cured my problem…..Ed Holmes
I had a similar problem on my B32 – loss of cooling flow and steam from exhaust.
Sailed back to berth – checked filter (OK), but being naturally suspicious took off inlet pipe and sucked…
Hard to suck any water through inlet pipe, so stopped to think. Coupling the dinghy pump to the water inlet pipe showed I needed a LOT of pressure to get any air flow through to the inlet. Booked drying piles for the following weekend (I wanted to scrub and antifoul anyway).
When I started the engine on the following weekend, the water flow was back to normal – but on drying out, there was weed in the water inlets on the leg. This was cleaned out.
When I have dried out a boat I always fill the water system once it’s back in the water before starting the engine. When I opened the filter to re-fill with water, there was a large clump of weed in the filter – it must have been pulled through the inlet pipe.
Hard to see how to prevent this – or cure it while afloat without swimming. One to watch for in future.Problem cured, fitted replacement sea water pump in weymouth as had tried everything else, and was successful, now have nearly continuous flow of water via exhaust at 2000 revs
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