Adam F Posted April 18, 2004 Report Share Posted April 18, 2004 I think most of you guys know the story behind the engine on BW - overheating alarm etc.... Anyway - I had the engine service - job done I hoped - new impeller etc. At weymouth last week the alarm came on again. Also 3 x today. It ONLY happens when at idle when she has been running for about 5 minutes and not moving - on it comes. The impeller seems to be pumping fine - good tell tale of cold water coming out. Any suggestions? My first thought is a stickly thermostat??? If poss would like to fix it myself before throwing loads of cash to a Marine mechanic. Oh, also it only happens when in the water - cant get the alarm to come on when running on muffs, Help!! Quote Link to comment Share on other sites More sharing options...
great white Posted April 19, 2004 Report Share Posted April 19, 2004 Be careful of that one Adam The fact that it doesn't come on with the muffs is down to a pressurised supply with the muffs on and a feed of cold water.I expect if you ran in a tank it would come on. It could be a problem inside the leg on the tube between the water pump casing and the block. Something as simple as a twisted seal can allow water to leak out and pressure to drop at idle speeds. which could give you your problem. Ask the service agent who changed your impellor as the box would have to come off to check. Charlie Quote Link to comment Share on other sites More sharing options...
Afishionado Posted April 19, 2004 Report Share Posted April 19, 2004 Quote........ Also 3 x today. It ONLY happens when at idle when she has been running for about 5 minutes and not moving - on it comes. I totaly agree that a pressured cold supply via muffs that are mains fed can mislead one into thinking one impellor is fine. Being a cynical old sceptic I wonder if #1 the impellor was really changed irrespective of what you were 'told'?, #2 If so was the housing they sit in changed at the same time?. The asymetric housing is either made from a metal casting with a hardened interior or plastic with a metal insert. If either of these are badly worn it can cause a big drop in water pressure feed to the cooling system AT SLOW SPEED. When the engine is running faster the higher rev' of the impellor makes up for the loss in pressure. All in all I would bet a pongy kipper to a quid that it is an impellor fault that is causing the problem. Mike PS if you go back to the dealer it is important to say that you paid to have the fault of the warning light coming on at low speed cured. NOT just to have the impellor changed. The fact that he says he changed the impellor is immaterial. You asked for the CAUSE OF THE LIGHT COMING ON TO BE CURED. Which obviously it hasn't. Therefore it's still up to the dealer to supply what you asked him to do and that should be taken into consideration if they wish to make further charges. Quote Link to comment Share on other sites More sharing options...
Adam F Posted April 19, 2004 Author Report Share Posted April 19, 2004 Hmmmm. I took the engine in to be serviced thats all. I did ask him to change the impeller - on the recommendation of the Mariner guy in Hayling. Ill try and run it an a barrell and see if it comes on that way - before making any decisions. Adam Quote Link to comment Share on other sites More sharing options...
Paul D Posted April 19, 2004 Report Share Posted April 19, 2004 Adam, I ran mine dunked in a dustbin ( probably done this already I guess ), but worked a treat for me !! Quote Link to comment Share on other sites More sharing options...
Afishionado Posted April 20, 2004 Report Share Posted April 20, 2004 Adam, I ran mine dunked in a dustbin ( probably done this already I guess ), but worked a treat for me !! I.ve done this too, but I found the dustbindragging through the water slowed the boat somewhat. Mike Quote Link to comment Share on other sites More sharing options...
great white Posted April 20, 2004 Report Share Posted April 20, 2004 Hi Adam I think you should talk to the repair agent and agree how to proceed testing at home in a barrel will not cure it. As Mike says the problem could be a worn casing as well as the old impellor. If the boat was run up and down Langstone Harbour a lot the silt may have got in and erroded the casing/ blocked the waterways. But it could still be the connecting pipework. Charlie Quote Link to comment Share on other sites More sharing options...
Bob F Posted April 25, 2004 Report Share Posted April 25, 2004 The overheating on my Suzuki was due to a faulty thermostat. But this only happened after 20-30 mins of idling, and could be reproduced using the mufflers. Bob F. Quote Link to comment Share on other sites More sharing options...
Afishionado Posted April 26, 2004 Report Share Posted April 26, 2004 Sorta like getting all hot and bothered over nothing then? Quote Link to comment Share on other sites More sharing options...
Bob F Posted April 26, 2004 Report Share Posted April 26, 2004 Mark B mentioned that it could be a build up of salt crystals in the block if the previous owner didn't flush the motor properly. Very probable seeing that the boat was moored. Apparently, there is some sort of special fluid (an acid) that you can use to flush out the block, but you must quickly flush out with fresh water to prevent too much erosion in the block. Quote Link to comment Share on other sites More sharing options...
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