jimfin Posted November 7, 2012 Report Share Posted November 7, 2012 Hi All We have a BMC 1.8 Diesel in our boat. Sometimes when motoring at about 2200 rpm it will jump to about 2500 for no good reason. Any ideas on what might be the problem!! Link to comment Share on other sites More sharing options...
Proper Job Posted November 7, 2012 Report Share Posted November 7, 2012 Does it jump to 2500 and then return back to 2200? Does the engine speed actually increase or is it just the Tacho reading? I am being serious as it's something I was asked to investigate. It turned out that the engine was staying at set revs. The fault was with the tacho. Link to comment Share on other sites More sharing options...
alan_fincher Posted November 7, 2012 Report Share Posted November 7, 2012 Bloomin 'eck! I think if ours could go over 200 rpm for very long I'd expect the boat to start shaking to bits..... 2,500 rpm ??? Respect !! Link to comment Share on other sites More sharing options...
jimfin Posted November 7, 2012 Author Report Share Posted November 7, 2012 Does it jump to 2500 and then return back to 2200? Does the engine speed actually increase or is it just the Tacho reading? I am being serious as it's something I was asked to investigate. It turned out that the engine was staying at set revs. The fault was with the tacho. Goes up to 2500 and would stay there. It is the engine revs. Tacho is OK. There is a fairly new filter in it. Fitted about 30 hours ago Link to comment Share on other sites More sharing options...
STUBAG Posted November 7, 2012 Report Share Posted November 7, 2012 Goes up to 2500 and would stay there. It is the engine revs. Tacho is OK. There is a fairly new filter in it. Fitted about 30 hours ago ? alternator load decreasing as batteries are topping up?.....mine used to do this (aaah, the good old days) Link to comment Share on other sites More sharing options...
Speedwell Posted November 7, 2012 Report Share Posted November 7, 2012 As you imply it happens suddenly, is there some play in the throttle cable or its linkage to the throttle arm on the injection pump ? Small amounts of air in the fuel system can have strange effects on running. This can be air getting in, air being expelled or air passing through the governer. My 1.8 has a slight leak in the injector pump and the air sometimes causes it to hunt at medium revs. A burst of high revs usually clears it. Arthur Link to comment Share on other sites More sharing options...
RLWP Posted November 7, 2012 Report Share Posted November 7, 2012 Alternator drive belt slipping? Richard Link to comment Share on other sites More sharing options...
jimfin Posted November 7, 2012 Author Report Share Posted November 7, 2012 Small amounts of air in the fuel system can have strange effects on running. This can be air getting in, air being expelled or air passing through the governer. My 1.8 has a slight leak in the injector pump and the air sometimes causes it to hunt at medium revs. A burst of high revs usually clears it. Arthur I think I might have this problem. I have felt around looking for a leak and noticed that the injector pump was a bit damp. Not dripping. Just damp with diesel. Is it hard the take off the injector pump and get it sorted? I have also noticed that it is getting harder to start. When heated for a full minute, it's like it's tring to start on 3 cylinders. Might be some air getting in. I have started winterizing it, so moght be a good time to do some work. Link to comment Share on other sites More sharing options...
RLWP Posted November 7, 2012 Report Share Posted November 7, 2012 (edited) I think I might have this problem. I have felt around looking for a leak and noticed that the injector pump was a bit damp. Not dripping. Just damp with diesel. Is it hard the take off the injector pump and get it sorted? I have also noticed that it is getting harder to start. When heated for a full minute, it's like it's tring to start on 3 cylinders. Might be some air getting in. I have started winterizing it, so moght be a good time to do some work. If you suspect you have this problem, it is most likely to be in one of the joints in the pipework - even one that doesn't seem to be leaking fuel Start off at the tank and check all of the joints with a pair of spanners Richard Edited November 7, 2012 by RLWP Link to comment Share on other sites More sharing options...
ditchcrawler Posted November 8, 2012 Report Share Posted November 8, 2012 I think I might have this problem. I have felt around looking for a leak and noticed that the injector pump was a bit damp. Not dripping. Just damp with diesel. Is it hard the take off the injector pump and get it sorted? I have also noticed that it is getting harder to start. When heated for a full minute, it's like it's tring to start on 3 cylinders. Might be some air getting in. I have started winterizing it, so moght be a good time to do some work. I had an old Land Rover like that. I use to operate the lift pump by hand before attempting th start it and push the air out of the self bleed system before it got to the injector pump. Link to comment Share on other sites More sharing options...
Speedwell Posted November 8, 2012 Report Share Posted November 8, 2012 I think I might have this problem. I have felt around looking for a leak and noticed that the injector pump was a bit damp. Not dripping. Just damp with diesel. Is it hard the take off the injector pump and get it sorted? I have also noticed that it is getting harder to start. When heated for a full minute, it's like it's tring to start on 3 cylinders. Might be some air getting in. I have started winterizing it, so moght be a good time to do some work. Mine is a leaking "O" ring in the throttle mechanism, which only started after I had the pump overhauled. (It's been back once which improved it but too much trouble to do it all again) Arthur Link to comment Share on other sites More sharing options...
jimfin Posted November 8, 2012 Author Report Share Posted November 8, 2012 Mine is a leaking "O" ring in the throttle mechanism, which only started after I had the pump overhauled. (It's been back once which improved it but too much trouble to do it all again) Arthur Can you tell me how to remove the pump. Do I have to remove the timing chain? Link to comment Share on other sites More sharing options...
Speedwell Posted November 8, 2012 Report Share Posted November 8, 2012 Can you tell me how to remove the pump. Do I have to remove the timing chain? It's fairly straightforward but messy. Just detach all pipes and cables, undo the 3 mounting nuts and remove it. The timing chain is not involved. Prepare for diesel spillage and protect pipes and pump from ingress of dirt. The pump has a master spline so it can only be fitted in one position, although there is timing adjustment, using the slotted mounting holes. An arrow and line give the supposedly correct timing setting (check how your is set)but if the timing chain has any wear the timing will need to be a bit advanced from that until no smoke is emitted when running. If you haven't already got a workshop manual, you should get one. They are available on line - there has been a recent post about where to get one. I could email a Calcutt one if you like. Arthur Link to comment Share on other sites More sharing options...
jimfin Posted November 8, 2012 Author Report Share Posted November 8, 2012 (edited) If you haven't already got a workshop manual, you should get one. They are available on line - there has been a recent post about where to get one. I could email a Calcutt one if you like. Arthur That would be great Please mail me at jimfinoc1@gmail.com The timing is OK as I have no smoke. I just found a workshop Manual on http://www.thenorfolkbroads.org/BMC%201.8%20Workshop%20Manual.pdf Is this the same one you have? Edited November 8, 2012 by jimfin Link to comment Share on other sites More sharing options...
Albion Posted November 8, 2012 Report Share Posted November 8, 2012 (edited) That would be great Please mail me at jimfinoc1@gmail.com The timing is OK as I have no smoke. I just found a workshop Manual on http://www.thenorfolkbroads.org/BMC%201.8%20Workshop%20Manual.pdf Is this the same one you have? When you remove and refit the pump watch out for the spring loading device (to stop spline chatter I think) which looks a bit like a metal mushroom where the head of the mushroom is a duplicate of the spline and master spline pattern on the drive spigot but is offset radially slightly and makes it more difficult to refit the spline. You need to get the head of the mushroom AND the spline inserted more or less at the same time. Roger Edited to add that you can see the part that I am talking about which is item 89 on page 12-15 of the manual that you have found. Edited November 8, 2012 by Albion Link to comment Share on other sites More sharing options...
jimfin Posted November 8, 2012 Author Report Share Posted November 8, 2012 Thanks. I found that and printed it off. Is there a seal kit I can get for this pump or should I leave it in to be checked over ect. Link to comment Share on other sites More sharing options...
Speedwell Posted November 8, 2012 Report Share Posted November 8, 2012 Overhauling these pumps is a complicated job requiring special equipment. It's not really a DIY job, although I did replace the "O" ring to reduce the leak from the throttle area. The ring came from the overhaulers and they lent me a spanner to fit the odd sized nuts(bolts?), which held the sub-assembly in place. I've emailed a copy of a workshop manual although I'm fairly sure it's technically the same as the one in your link. Arthur Link to comment Share on other sites More sharing options...
jimfin Posted November 8, 2012 Author Report Share Posted November 8, 2012 Received all that. Thank you, Thank you all for your input. I am wiser over the last 2 days. Now not to make a mess of it. I'll try and keep you posted. Link to comment Share on other sites More sharing options...
jimfin Posted November 20, 2012 Author Report Share Posted November 20, 2012 When you remove and refit the pump watch out for the spring loading device (to stop spline chatter I think) which looks a bit like a metal mushroom where the head of the mushroom is a duplicate of the spline and master spline pattern on the drive spigot but is offset radially slightly and makes it more difficult to refit the spline. You need to get the head of the mushroom AND the spline inserted more or less at the same time. Roger Edited to add that you can see the part that I am talking about which is item 89 on page 12-15 of the manual that you have found. Can this also cause a problem when taking the pump out. I have all nuts ect disconected, but the pump will not come all the way out. It has only come out about 1/4 inch. I have jiggled it around and tried a small bit of leverage with a screw driver, but it will not come out. Any other advice before I take off ther timing chain cover!!?? Link to comment Share on other sites More sharing options...
RLWP Posted November 20, 2012 Report Share Posted November 20, 2012 How did you mark the timing? Richard Link to comment Share on other sites More sharing options...
jimfin Posted November 20, 2012 Author Report Share Posted November 20, 2012 How did you mark the timing? Richard I marked it with a center punch. But I think you are asking if I put the crank in a certain position before I started. If this is the question. I did not. Link to comment Share on other sites More sharing options...
RLWP Posted November 20, 2012 Report Share Posted November 20, 2012 I marked it with a center punch. But I think you are asking if I put the crank in a certain position before I started. If this is the question. I did not. No, I wanted to be sure you had done something like your centre punch marks. Richard Link to comment Share on other sites More sharing options...
Albion Posted November 20, 2012 Report Share Posted November 20, 2012 Can this also cause a problem when taking the pump out. I have all nuts ect disconected, but the pump will not come all the way out. It has only come out about 1/4 inch. I have jiggled it around and tried a small bit of leverage with a screw driver, but it will not come out. Any other advice before I take off ther timing chain cover!!?? Not to my knowledge. The end of the mushroom stem just slides into part 45 (I think) on the pump drive and that then just slightly radially misaligns the head of the mushroom with its splines from the input drive shaft. The stem of the mushroom then acts as a torsion spring thus stopping drive spline chatter I believe. The only thing that I remember being difficult about the job was access to the third securing nut between the pump and the block which IIRC I modified a spanner to reach behind and give some movement to as it is all rather tight for access behind there. I don't think that you should have to remove the timing chain cover at all to be honest. Roger Link to comment Share on other sites More sharing options...
RLWP Posted November 20, 2012 Report Share Posted November 20, 2012 A quarter of an inch sounds like the clearance at the back of the drive gear. Perhaps you could try being a little more forceful - gently though Richard Link to comment Share on other sites More sharing options...
Speedwell Posted November 21, 2012 Report Share Posted November 21, 2012 Not to my knowledge. The end of the mushroom stem just slides into part 45 (I think) on the pump drive and that then just slightly radially misaligns the head of the mushroom with its splines from the input drive shaft. The stem of the mushroom then acts as a torsion spring thus stopping drive spline chatter I believe. The only thing that I remember being difficult about the job was access to the third securing nut between the pump and the block which IIRC I modified a spanner to reach behind and give some movement to as it is all rather tight for access behind there. I don't think that you should have to remove the timing chain cover at all to be honest. Roger Just wanted to agree that there is no need to remove the timing chain cover. When I took my pump off, I wasn't aware of the mushroom device. Whether it hadn't been fitted or stayed in the pump, I don't know. Arthur I see Monkey 1 has just posted the perfect guide to fixing the leak at the throttle spindle. Arthur Link to comment Share on other sites More sharing options...
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