Cooling Water tell-tale

boatone

boatone

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Just a few cables from Boulters Lock
www.tmba.org.uk
Raw water cooling intake and exhaust on my P32 is via the VP 270D legs and therefore not possible to actually see that water is circulating. Has anyone found an easy answer to this problem? I had an overheating problem yesterday which I can only put down to either a blocked intake or a failure of the impeller to prime succesfully on start up. Either way, some visual confirnation would have been very useful!

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Cannot help on tell tale,but removed exhaust risers on my old boat recently,just for something to do(princess 25) and they were totally clogged with corrosion crap.How ANY water was going through I have no idea.
The engine had no obvious signs of overheating previously.See my post on Volvo Penta users site for details under legs bit.
 
Whatever caused the problem cleared itself which is why I suspect the blocked intake or impeller priming as the cause. After lifting leg to check for plastic bag or whatever and allowing engine to cool down it started fine and was ok for rest of day including several start/stops thru locks etc.
My real questiojn is how to create some visibility for raw water circulation. Did think to install weed filter but precious little room!

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Replace one of your coolant hoses with a clear plastic one, you will then see the water flow, or put a small take off hose anywhere in the in the raw water side and a tap on the end, open tap to check for flow, useful as a salt water deck wash aswell! Can you not tell by the sound of your exhausts oif there is water coming out with it, I can, but there again I have heard the difference before.
 
As CS says, you can replace the pipe that runs from the forrard side of the oil cooler to the bottom of the jabsco with a clear peice. To check on the outward flow of the heat exchanger there is a square plug that unscrews on the right hand side of the heat exchanger, undo this whilst on tickover to monitor the flow.
Hope this helps
Syd
 
What about putting a low pressure gauge on , connect to the arse end plug on the manifold .
It only needs to register a pressure difference and you'll know the water is ok .

The other option is a water temp gauge so that you can monitor the discharged temp which of course would indicate low / or no water re the heat of it.

I'd go for the pressure gauge my self , although a bit of a job once done you could then supply every one with details of what / how you fitted it and where you got the parts from.

Cheers
MIck

http://homepage.ntlworld.com/boats
I want a big steel ex trawler / tug v / cheap or swap for tug
 
The best way is to do what Broom boats do as standard, on say the oil cooler, there will be a plug, 3/8 bsp, remove it and put in a union tale type, connect hose through hull skin fitting above waterline, you will then see water coming out, just the same set up as a shaft drive boat for the feed to the sterngland lube pipe, if you do not have an oil cooler, as I dont know which engines you have, then you may have a spare plug in the heat exchanger.

Paul js.
 
Syd,
I know you had AQD32's on an earlier boat..............
There is a secondary raw water outlet spigot on the exhaust elbow ....all the handbook says about this is '....a part of the cooling water is led through seperate outlets.....' and the part description is 'by-pass water hose' The hose goes down to a seperate outlet spigot on the leg assembly. Any idea why this is there/what its for? Would seem to be an ideal place to tap in a tell-tale to transom outlet above waterline.

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Now thats a good idea. That bypass outlet on your exhaust elbow you mentioned would be the ideal spot for adding a tell tale. Inside the exhaust elbow is a tongue shaped flap of metal which splits the elbow horizontaly. This is where the exhaust gases and raw water meet, with the raw water flow on top and the gases in the lower half. This flap of metal is one of the main causes of overheating in the AQD32's, when it corrodes and expands it restricts the flow of both water and gas. The bypass is there mainly to stop water under pressure backing up and entering the exhaust ports. I reckon a 'T' connection on the rubber pipe that leads from the bypass gromet on the elbow to the transom and then a skin fitting above the water line as Paul Suggests would be the dogs goolies place for a tell tale.
Cheers
Syd
 
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