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Message 11 of 11
Posted by member Peter Cox on Wednesday 24 January 2018
I took out one of the screws and measured it as M5 8mm in A2 S/S (A2 marked on head). I've found a supplier of M5 8mm in A4 S/S, which is said to be better for salt water, available in sachets of 30. Having said that, the A2 one I took out looked in very good condition after 2.5 years.
https://www.westfieldfasteners.co.uk/A4_ScrewBolt_HexHd_M5_THRfull.html
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Message 10 of 11
Posted by member John on Friday 12 January 2018
Stainless Steel Hexagon Head Set screws are available from Farnell http://uk.farnell.com/
You will probably need about 12mm length, M4 or M5, take one out to check. eg farnell part code. 1420749
These cost about £9 per 100, enough for your friends as well rather than the £1.00 each from chandlers.
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Message 9 of 11
Posted by member Peter Cox on Friday 12 January 2018
Yesterday at the London Boat Show I discussed this problem with E P Barrus and Mike French. Both denied that this was a 'known problem' but both seemed to know a bit about it. Basically the current (new?) advice is to change the screws every two years; S/S is better than brass but the latter is passably OK if changed regularly, however do not use mild steel. The Barrus rep also advised coating the screws in Permaflex sealant but Mike French did not agree. To reinforce the need for regular replacement, apparently the official replacement impellers now come pre-packed with replacement screws.
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Message 8 of 11
Posted by member Hardy Editor on Friday 1 September 2017
Hi Peter,
I did indeed mention to Oliver James about this problem when I last contacted Hardy Marine, and forwarded him the details which you kindly supplied to me. Oliver was pretty shocked. I’ve not heard anything further as yet, but I do think as a Club we should approach Yanmar directly and see what they have to say.
I’m afraid I’ve not had the time to do this myself, although it was my intention to do so. I’ve only just completed the September issue of the Hardy Owner magazine and sent the file off to the printers for proofing.
However this does sound like a very serious problem, Peter, and we really should take it upon ourselves to investigate further.
Perhaps a contingent of Hardy Owners should make a call (not in the euphemistic sense!) at the Yanmar exhibition area at the Southampton Boat Show – September 15th–24th (Stand E050 – email: customerservices@barrus.co.uk) and politely point out the facts as we understand them and ask them to comment on our findings. I’m game if anyone would like to join me. I’m unable to go on either the Preview Day (Friday 15th) or the closing day (Sunday 24th) but will let you know when I can visit, so perhaps we can meet up.
Anyone interested? Just contact me and let me know.
Marie O’Connell HOC Editor
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Message 7 of 11
Posted by member Peter Cox on Friday 1 September 2017
Another twist to the saga: according to my marina workshop manager, replacing the original brass screws with S/S ones is an improvement but even the S/S screws do not last for ever, just longer than the brass. The 36 that nearly sank in my marina already had the S/S screws but they too failed. The manager said that the real problem is that the cover plates only have four screws, ideally there should be six or eight, so that if several fail, the cover plate will stay on, at least for some time.
Marie tells me that Hardy have taken the matter up with Yanmar, but I'm not holding my breath for a reply from Yanmar.
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Message 6 of 11
Posted by member Simon Kidd on Monday 24 July 2017
Quite Shocking to hear about this, brass is just not suitable for use in salt water. I've found a few issues on smaller Yanmar engines, though it's very rare to find similar issues on Volvos (Can happen though).
My old Caterpillars had Johnson Pumps and no issues there (though heat exchangers were a different matter!!, nor the Sherwood pumps on the Onan genny.
I've found a number of vessels with corroded A/P bracket stern gland and rudder gland bolts recently (Dezincified thus now made of copper!) - make sure they are all checked whenever ashore - use a good hammer and look at the bolt heads for the pink colour as a tell tell for dezincification..
I'll be keeping a sharp lookout on the pump covers, and sticking with Outboards for now!..
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Message 5 of 11
Posted by member DARKIVY on Wednesday 28 June 2017
Thanks Peter
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Message 4 of 11
Posted by member Peter Cox on Tuesday 27 June 2017
Bad news concerning a Hardy 36 next berth but one to me (not an HOC member) and I think with the same Yanmars as me; apparently the impeller cover plate fastening screws failed and the boat nearly sank. Second-hand news in the marina is that the bill will be in excess of £70k. Check/replace yours!
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Message 3 of 11
Posted by member Peter Cox on Thursday 18 June 2015
The boatyard has now replaced the brass screws (sorry - not bolts, as I originally wrote) with stainless steel ones. Both pumps had to be removed from the engines; fortunately this gave access to the 'back' of the screw holes so that the remaining stubs of the screws could be unscrewed, after a little modification, from there, without drilling and tapping. I took the opportunity to have the impellers replaced. The cover plates were a bit worn, so were reversed. The boatyard said that the other boat, not a Hardy but the same engines, had one of the cover plates held on by only one remaining screw; disaster narrowly averted!
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Message 2 of 11
Posted by member John on Tuesday 9 June 2015
The same problem Peter. I guess a bit of salt water gets in and causes corrosion as the engine gets older. Some had a bit of thread left so was able to remove these with WD40 and patience, although not easy to get at! One had to be drilled out and retapped, done in situ but would not be possible with some of them.
They seem to be M4 brass (Yanmar Product Code WPS-M4) and cost £1 or so each. These are actually Johnston pumps.
I was thinking of replacing these with phosphor bronze studs and then using nuts to fix the cover, and possibly a little waterproof grease on the threads to minimise corrosion.
Best of luck
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Message 1 of 11
Posted by member Peter Cox on Monday 8 June 2015
On my twin 6LPA-DTP engines, several of the bolts securing the impeller cover plates have simply corroded away or the heads have fallen off, so that the remaining studs will have to be drilled out. Not a cheap job, as the entire pumps will have to be removed. My marina workshop says that this is the second of these jobs they have had to do on this type of engine in the last few weeks. Why does Yanmar do this? If you remove the cover plate on any Yanmar, it might be worth renewing the bolts as routine.
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