Tony Brooks

FWIW, not having specific experience. Looking on Google images, it looks as if that solenoid may be mounted on a bracket on the engine, if this is so the first thing I would do is move it to a mounting somewhere on the boat. It seems solenoids like this and relays mounted on the engine tend not to take kindly to the engine vibrations. The diagram in a manual I found looks very like an ordinary relay rather than a solenoid. If it is a small (rectangular box) relay, then I would change it for an inertia starter solenoid. You say it keeps failing, exactly in what way?

The one I saw was two half couplings welded together, but it could be machined from a large diameter metal "rod" or even hard wood. I think that I would have changed the studs on the back for set screws, but I bet they are an odd thread for nowadays like UNC. As long as they stayed oil free we fund them good flexibles and if not oil free, a readily obtainable spider - every town had a BMC garage at that time. refitting the spider and keeping the two faces aligned was the problem.

Yes, exactly that.

This could well be the case, as I find silicon hoses rather more squishy than normal rubber cooling system hoses.

The spider is the inboard flexible joint on a Mini drive shaft. Take the rubber and steel spider and put it between two castings and you have the OP's flexible joint that is inboard as far as the boat is concerned, it is not an outdrive and it is not a CV joint. In the automotive application, it had it transmit torque through the angular misalignment cased by suspension movement and also rather less caused by steering movement, although that was largely eliminated by having the CV ball and cage in line with the steering ball joints (pivots).

No, I am on about a small bronze casting screwed to the outside of the hull, over the water inlet hole. Once you have a feel around, you will know exactly what you have. You always get little bits of weed, small water snails, broken matchsticks etc through the external strainer, but they can cause problems it bread wrappers sucked into the getting stuck and not dropping off.

I think they had a nice cast bronze slotted strainer when new, but yours was probably knocked off years ago.

No need for apologies because this lot is spread across at least two topics. If I was not so familiar with BMC 1.5s of that age I would have been lost weeks ago. I am also a bit sceptical about the alignment because with that stud in place he could not rotate the two halves independently. He should have taken the coupling out and used a dummy one to do the alignment, but that is hardly practical. It is also worth noting that this particular type of flexible is excellent at developing a set, so the two alloy faces are no longer parallel - hence my advice not to mess with the U bolts. The aluminium casting at the back end of the flexible normally has a raised disk, a land, around the centre. The metal shaft half coupling normally has a matching recess machined into the face. When the two are brought together, the land should slide perfectly into the recess in the half coupling. This ensures that the radial alignment is correct. You would have ideally removed the remaining stud so it could not interfere with the alignment, and allow you to rotate the flexible coupling and the shaft half coupling to ensure nothing is bent - this is what Peugot106 was talking about. What you did would not test for angular misalignment because the bolts would pull the faces together. With no studs interfering with the procedure and the two parts pushed together by had, rotating one part and seeing if the gap at one point alters checks for something being bent. See note below. Then using feeler gauges to ensure any gap at any point around the joint is less than 5 thou at any point ensures the engine and shaft is properly aligned. NOTE BELOW - with that flexible I am confident there is likely to be indications that something is bent because of the set they tend to take, but I hope this is not the case. As I intimated, this coupling will probably accept more misalignment as many others.

True, but in this case I would prefer to have a feel around to be sure any grid is clear - who knows, it might be those horrible muscles that collect on some narrowboat hulls.

Stable yes, damp RESISTANT yes, but the stuff I built two sheds out of have all gone bumpy where the wood slivers seem to have swelled. OSB3 used.

I bet that exposed OSB in the heads goes all bumpy with damp, even if it is sealed/varnished. I also wonder if the OSB rectangular panel around the porthole in the heads is hiding water leak damage.

That one should be fine, so another idea out the window. I think that we can assume this is something like a Meakes Madeira or Seamaster 27 and if so the raw water intake often had some kind of grill or grid on the outside of the hull. I would want to make sure that if you have one, it is totally clean, now lengths of weed or plastic film hanging off it. It may involve getting nice and cool.😀

I thought we were talking at cross purposes. The hose you show is a raw water COOLING hose, not an exhaust hose. That is as it should be. You have an exhaust manifold that was originally used for direct raw water cooling, but looking at the pipe run, I suspect it runs from the heat exchanger/header tank mounted across the front of the engine. If so, I assume that you have had the heat exchanger end caps off and cleaned out the crap - not that that should stop the pump working as you described. I wonder if the Jabsco pump is the correct one, it should have an impeller at least 3/4" wide, but again that would not stop it pumping, but if you have the keel cooled pump its output may be so small it is being boiled off in the exhaust. Sorry about this, but I think another photo, just to be sure, although this is a very long shot.

That sounds wrong to me, because it sounds as if it is on the exhaust side of the mixing elbow, so it will have no water through it to cool it. It is a wonder it has not caught fire. Any chance of a photo, because I can't picture it. I agree with KIB about the possibility of an air leak on the suction side of the pump, but that often cause a reluctance for the pump to prime, but when it does, they often stay pumping

He has done, and it is essentially a Mini rubber spider held into two cast aluminium flanges by U bolts. It should cope with angular misalignment marginally better than many of the other single flexible element type couplings, and even a small amount of radial misalignment because the rubbers will distort on the metal spider. I have already tried to explain to the OP how t go about the alignment, and from what he writes I think the angular alignment is near enough, but as he has not clarified that the land on one half does not bind on the side of the recess of the other half I am less sure about the radial alignment, but as I say, apart from the Aquadrive or long Centaflex type his is probably more alignment tolerant than most. FWIW, his rear engine mounts are of a type that puts rubber "cylinders" around the hold down bolt into compression, so the amount of fore and aft movement of the engine and shaft as he goes between ahead and aster will be far less than that when modern mounts are used. Much of this is covered in his first conversation with us.

As KIB advised, but in a bit more detail. So that includes the full exhaust hose and the exhaust mixing elbow that is often sold as part of the manifold in a marinising kit. You don't say what type of boat this is, but seeing you give your location as Oxford and the boat name looks very like it is to meet the EA requirements re naming, it may well be a cruiser with a rubber exhaust hose, and if so such hose can and do delaminate at a point along their length and the delaminated section starts to burn through when the raw water fails. This causes a pocket that lets exhaust gasses (and water) past when at idle, but at higher speeds the gas flow pushes the "pocket" across the exhaust pipe, partially blocking it and allowing pressure to build up to such an extent it pushes back on the Jabsco impeller vanes and bends them back this stops it pumping. Seeing the cost of decent exhaust hose, I am far from sure you changed that. The delamination can be difficult to spot, even with the hose off the boat and pulled straight. Likewise, I would not call the exhaust mixing elbow a pipe. These can and do gradually block with salt residue or in the case of the Thames lime scale. This also causes a build up of exhaust back pressure, pushing the impeller vanes back. You have described pretty much the classic symptoms, unless you have (say) a bread wrapper caught on the raw water inlet so as you speed up the engine and water flow into the boat speeds up it gets sucked over the inlet, only to drop back when the engine stops.

The B series 1500CC units were Navigators, so the name Vedette implies a 998CC(ish) A series - as long as it has been correctly identified. I very much doubt this is a marine conversion, but a factory built unit by their marine & industrial arm. The distributor placement is not unusual for the marine units of the time.