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wetfoot

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  1. Thanks Richard, That's similar to the manual I was looking at (although mine was in English (:-) ). I can now see the intermediate gear and it all makes sense (apart from the knocking!).
  2. Thank you Boater Sam, that's very useful information. That explains why the schematics diagram appears to show the forward gear smaller than the rearward. Makes sense now to double up the input shaft to act as the layshaft as well. Also handy to know that forward gear = reverse of engine rotation. The knock is the same in forward and reverse, although not in neutral so if the intermediate gear is always engaged, even if its secondary gear is disconnected from the output shaft then it could be the intermediate gear. Otherwise it might be to do with the output shaft as that is the only thing turning in forward or reverse but not neutral.
  3. My son's recently acquired boat has a technodrive TMC60 gearbox that we had to take off and repair as the bolts holding it to the engine plate had sheared. (bolts are 8mm but holes in engine plate were 10mm so no wonder they sheared). We got it all back using bushes in the holes but I have a couple of questions about the box if anyone is able to help me. 1) The boat runs OK and drives in forward and reverse but when the prop is turning there is a rhythmic knocking sound near/inside the gearbox. It's not there when in neutral so it must be coming from somewhere after the drive plate. The gear box is pretty simple so I can't imagine what could be knocking inside it. Do these boxes usually make such a sound? If not anyone any idea what it could be? 2) With the engine off and the box in forward or reverse gear my son could can rotate the prop shaft. That shouldn't be possible as he should be trying to rotate the engine as well if its in gear. He said he could rotate one way but not the other. How is this possible unless the clutch is seriously slipping, which it can't be as the boat drives well. 3) This one I'm embarrassed to ask as I've dismantled car gearboxes in the past and rebuilt them and they are a lot more complicated than the TMC 60 so I should be able to work this out myself. Just in case we need to take the box apart I've looked at several exploded diagrams and cannot for the life of me see how it goes into reverse. All there seems to be in there is an input shaft with a gear on it meshed with another gear on the output shaft via a clutch when in forward or else via another clutch which engages a different gear, also on the output shaft, when in reverse (or the other way round). The diagrams seem to show that the smaller gear is not meshed with anything though. I cannot see a layshaft or layshaft gear in the diagrams so how does the box make the output shaft reverse rotation? You need to insert an intermediate gear between the input shaft and output shaft to reverse the output rotation so there should be three gears in the box somewhere. ?
  4. @Tony Brooks The engine does not exhibit any particular vibration or misfire, none more than one would expect, in fact it runs quite smoothly. The engine is only eight years old and I know the boat has been stationary in a marina (with the broken manicooler removed) for at least the last two years. The boat was bought with the manicooler broken and removed from the engine so we had some idea what we were letting ourselves in for. But if the engine did have excessive vibration I would have thought a cracked manicooler would be the least of our problems. I did look at the Barrus website but found it less than helpful unless you knew exactly what you wanted. I also rang them as suggested and whilst they were quite polite and helpful, they said they couldn't do anything without a 'shire number', which was apparently supposed to be stamped on the rocker box cover. As I had no idea what a shire number was and certainly could not read any numbers that may have once upon a time been stamped on the engine I could proceed no further with them. I've purchased the smaller manicooler in my photo for my son simply because it is the only thing I had seen that was remotely like what was originally fitted, although since the purchase I see that those like in the photos uploaded by Scholar Gypsy would have been more suitable as they fit closer to the engine. In fact it was precisely seeking information such as Scholar Gypsy provided that led me to post my question here in the first place, although it was just a guess that canalworld would be frequented by people who knew about building and repairing engines used in boats, rather than just those who used boats for recreation. Thank you to everyone who has posted replies. I now know what it is and and what it is used for and since I have bought a replacement I guess my thread is over (at least until this one breaks). Regards
  5. I really don't want to get sidetracked from a helpful, technical discussion on marine engines into an emotive discussion on waste disposal. However I feel I must respond by saying 'who wants to go to a marina, park nose to tail with your neighbours, pay through the nose for everything they offer, then hook up to mains water, electricity and (pump out) sewers'? Might as well live in a terraced house. Composting toilets are very widely used and can be clean and environmentally friendly - if used properly ie not simply emptied into a 'normal' toilet or elsan point as that rather defeats the purpose. Dumping it in an elsan point uses a lot of water and effectively gives your sewage to someone else to deal with instead. I can see why marinas would object to having a large quantity of waste disposed of at once at such a point, especially if those doing so were irresponsible and made a mess. But apart from the plastic in a nappy, the solid contents of a compost toilet consist of practically the same chemicals, bacteria and other substances as a baby's nappy or adult's incontinence pads, except that being dry it does not smell and is easier to handle. I understand it falls under the same disposal regulations as such items as nappies (except, as you pointed out, those regulations made up by private land owners such as marina owners) although as it can be classed as dry sludge it is more suitable for direct land use, further composting or landfill via the normal waste collection systems. Personally I'd rather have dry poop in a sealed container (not under my bed) for a couple of months than 300 litres of mixed up urine and poop slurry sloshing around in a tank that I can't do anything with without going to a marina and paying someone to waste another 300 litres of fresh water to dispose of it down the severs. But each to their own. (BTW the comment about your engine bay was intended as a compliment.)
  6. Thanks for the pictures. That helps a lot. In the end I have contact the person who had the cooler in my original pic and arranged to buy that from them as I think it will fit. It still has stub pipes but the cooler itself is smaller, rather like the picture from Scholar Gypsy so will not create such a large bending moment on the welds. I don't have a very useful picture of the original, broken one from my son's boat but you can see it in the attached picture. It's the big black black box with the car radiator cap on the left of the rocker box cover. (I painted it black after the repair and added the strap down to the support that I fabricated) The depth is almost the same as the width, ie from the side it is almost square. I'd estimate when full it would hold about 6 litres of coolant, about 6Kg, plus about 5Kg for the cooler itself, plus some weight from the exhaust pipe, means the pipes are (were) supporting over 11 Kg of vibrating mass. The other photo shows the support frame that I fabricated before the repaired cooler was fitted, with legs down to the engine side of the engine mounts and also across to the flywheel cover. It's made from 5mm thick steel strapping with a thin layer of closed foam padding on top, apart from the top strap which is only 1.5 mm thick. However I've just driven down to my son's boat in London and all the flange welds have failed again and the cooler, complete with all four pipes can be pulled completely out of the flange bolted to the engine block. Good job I bought the other one as they seem hard to come by and very expensive. But if it doesn't quite fit it will be simpler to make a flange converter than a whole new cooler. But I think it will fit as the engine it comes from is the same make, bore and stroke as my son's, just a slightly smaller HP so I'm guessing it's the same engine block. @Alan de Enfield One day my son's engine bay will be as clean and pretty as yours ! Priority at the moment though is to get the engine working nicely, then get the solar panels working to charge the new Lithium batteries and strip out and remove a full size, ceramic, pump out toilet, its collection tank tank and two macerator pumps that have been sitting unused, full of sewage, for two years and then replace the whole lot with a compost system.
  7. @BEngo Yes there is a flexible, insulated, exhaust pipe bolted to the outlet pipe of the manifold, which then goes out of the side of the boat. From the bit I can see before the insulation starts it looks the same type as the one you got from Uxbridge Boat Centre. Although that 1.3 m of pipe is not supported so probably added to the weight and vibration on the exhaust manifiold, which is then transmitted to the welds on the flange. I guess ideally there should be short flexible pipes between the manifold flange and the water cooling part to prevent stress fractures, although I suppose having solid aluminium pipes would aid in the cooling of the bits of pipe between the flange and where the exhaust is being cooled by allowing heat to travel quickly towards the cooler parts. I'm certainly learning a lot about marine engineering. It's a whole new world!
  8. OK, thank you for the information, very useful. I'll contact E P Barrus to see what they can do. Thanks also for the info about blanking the manifold core pipes. That makes sense as nearly all of the images I looked at had such a core so I assumed they were not what I was looking for. Simply blanking those pipes would convert the manifold into something similar to what my son has. You are correct that when my son bought the boat a month ago the only way the large, heavy, manifold was supported was simply by the exhaust inlet pipes so it is not surprising that the aluminium pipes had suffered stress fractures and were broken. I could also see that they had been repaired more than once in the past due to similar fractures. I got the manifold repaired at a local agricultural engine repairers who were familiar with yanmar and did aluminum welding. Then I fabricated a steel support shelf for the manifold which attached both to the engine block sideways and to the engine mounts downwards (on the engine side of the flexible mount so it vibrated with the engine). However after moving the boat 21 miles my son says the pipes have broken yet again so its now time to look for an alternative. I'm even considering buying a TIG welder and making one myself!
  9. Thank you Tony, I'm not sure why you seem to have taken offence at my queries. I don't know anything about boats or boat engines (I'd never even heard the term marinisation until now). I was simply hoping that someone on this forum was an 'expert' relative to me. My activity as an expert on forums for other topics usually consists of knowledgeable people helping out those less knowledgeable, if necessary in simple terms, without sarcasm and without expecting to be paid. The picture was simply one I got from Google images but it is for a different engine. It's the only picture I could find that looks like my son's one. All the others have an elbow that seems to actually inject the water into the exhaust gas, not simply surround the exhaust pipe. Are you able to tell me who the major UK mariniser of Yanmar engines is so maybe I could contact them?
  10. Why does the exhaust manifold in a boat 'glow red hot' when the same manifold in my 2 litre diesel car sitting at 1500 rpm doesn't? From what I have researched it is unlikely to get more than around 900 Dec C. Yes I heard about that, hence my question about whether the water cooled manifold was really necessary iI it? That would be good to know. If that is a picture of a water cooled manifold for the 4JH4AE engine then my problem is solved. I can simply buy that one. However as I do not really know much about these things I am relying on all you experts to help me out. Thanks, I did look there but all their products seem to assume you are using sea water to cool the manifold, not the ordinary engine coolant - unless I am looking at the wrong thing.
  11. My son has bought a broad beam canal boat fitted with a Yanmar 4JH4AE engine. The engine had what appeared to be a home made, aluminium, water cooled exhaust manifold with the exhaust gas going straight through an aluminium box about the size of a shoe box. The 'shoebox' had a radiator style filler cap on top and two connections about 30mm diameter for the engine cooling water/antifreeze to circulate in and out on its way to the skin tank. That's it, no connection to the canal water or the 'elbow' I've heard so much about. (I've found a picture of something very similar at attach it here as I don't have access to the real thing at the moment) Due to its size and weight the exhaust inlet pipes have cracked several times in spite of being re-welded, so I'm looking to replace the whole thing. First of all, can someone tell me the point of it? is it simply to keep the engine bay a little cooler? It realise it will cool the exhaust gasses but they leave the boat after about 1.5m so why should I care if they are hot? Secondly can anyone tell me where I might be able to get a replacement or even what the correct name is of the thing I should look for? All my searches for 'water cooled exhaust' or 'manicooler' come up with loads of stuff about an elbow that corrodes and directly injecting sea water into the exhaust gas which this doesn't do.
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