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  • #49263
    Alan Worland 1
    Participant
      @alanworland1
      Crikey guys – lets not start a fight!! I have no immediate plans to build anything to use this engine, it just started as a little project to get an antique engine  to run and went from there!
      I think your comment Chris about oil/petrol mix is quite interesting, my son ran 2 stroke bikes for a while and the ratio you suggest rings a bell.
      I have measured the stroke of the engine and it measures the ‘stroked’ 1 inch
      Further investigation has revealed what I think is a major fault – the points cam breaks at 11 degrees BTDC, BUT, the cam only allows the points to close for a duration of 48 degrees – so for the rest of the cycle the points are open with the coil not ‘on’
      I would have thought the cam should have had the coil ‘on’ for the cycle only breaking when required for the spark?
      Anyway while I was measuring the timing (piece of masking tape around the flywheel) I took note of other timing events
       
      Piston starts to clear the exhaust port at 127 degrees ATDC
      Piston starts to uncover inlet venturi at 43 degrees BTDC
      Piston fully covers inlet venturi at 43 degrees ATDC
      Dont know if these figures are what might be expected
       
      Really interesting with regard to the catalogue – would love a scan of it?
      Your engine looks pretty similar to mine although I note the points on mine are on top and yours are on the side of the crankcase and my fuel tank appears larger – can you appreciate the timing is not that easy to adjust accurately?
      With regard to the oil in the mix I can only be guided by those with more experience than myself, I used 2 stroke oil because it is a 2 stroke!
      Here are some photos of the culprit!
       
       
       
       
       
       
       

      Edited By Alan Worland on 27/02/2010 21:19:37

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      #49265
      Ramon Wilson
      Participant
        @ramonwilson3
         
        Hi Alan,
        I have stripped this engine down this afternoon and feel fairly certain this one is home built. I dont know what your piston is like but this has a shallow slope on the exhaust side with a much shorter one on the transfer side. This one is a composite with an ali top riveted to an ali insert for the gudgeon pin clamping a cast skirt.

        My intention was not to insult you with the suggestion of wrong assembly merely  a suggestion on something else to check.

        The reason I think this one is home built is that virtually all the flat faces appear to be filed including the piston top.

         
         
        The crankshaft is made of three parts the pin and shaft silver soldered in place.
        The piston seal is not particularly good but I will carry out Hughs recommendations and see where they lead to. I will have to get a new plug (or make one) as this one is broken.
         
        Regards for now – I’ll keep you posted on developments.
         
        Chris – I’m not quoting from ‘hearsay’ per se. The two people I contacted are well known for their knowledge of vintage model engines. One earns a living repairing, making parts and building replicas the other has  a lot of experience with using them in tethered cars and hydoplanes. Their advice is possibly not perfect in some quarters but I’ve known one a long time and of  the others experience for about the same.
         
        However, at the risk of possibly being castigated for quoting from such, perhaps you will be reassured by the fact that Westbury who, in his book Model Petrol Engines (of which I have literally just obtained a copy this evening) states and I do quote (p159)
        “A 250cc motor cycle may run quite satisfactorily on a mixture of 1 part oil to 16 parts petrol while a 5cc engine may require 1 part oil to four parts petrol” unquote .
        The ‘technical’ reasons why a small two stroke petrol engine requires this amount is not something I know the answer too as yet but standard glo fuel is either 75:25 methanol/oil or 80/20 depending on the engine (I had better add – of the ones I’m used too!)
        He goes on to say that the most suitable proportions are found by trial and error and represent a compromise between under oiling and over oiling.
         
        It would appear that four to one is a probably a good starting point then.
         
        Kind regards – Ramon
        #49266
        Alan Worland 1
        Participant
          @alanworland1
          Hi Ramon
           
          I think our posts have crossed!
           
          I attempted to put some photos up – didn’t work, but I believe if you click on them you will get there!
          I remember file marks on my piston crown as well
          Shame about the plug – mine is a Champion Y-5, don’t suppose they are still available.
          Do you believe your piston is the right way round?

          Edited By Alan Worland on 27/02/2010 21:40:14

          #49267
          Ramon Wilson
          Participant
            @ramonwilson3
            Hi again Alan,
             
            I’m afraid that beyond the most basic facts the mysteries of the ignition system mechanics are yet to be discovered.
             
            However the cam on this appears to be the same as yours closing for a very short period relative to the lift. (This flat also appears filed on)
            As you see it the points have just rotated around the engine, currently they are loose and will rotate to the same top position as yours. As it stands the position can be locked with a  screw but a short threaded bar knurled on the end would help move it while running and allow locking which is something I’m certain I have seen on other engines elsewhere.
             
            BTW as a matter of interest is yours assembled with round head 1/8 whitworth screws?
            (The four cylinder head bolts on this go in no more than three or four threads!)
             
            Your photos appear to show what Hugh described as the original tank – made from a casting. This one has just a piece of tube with an end turned from flat plate let in.
             
             
             
            #49269
            Ramon Wilson
            Participant
              @ramonwilson3
              Yes Alan, quite happy with the direction – short side to the transfer.
              As above  – found the pics okay – thanks.
               
              I believe 1/4 x 32 plugs are now readily available – I’m sure I saw that Just Engines sell them. Whether you can get 3/8 though is another matter but an adaptor could be made. It would be nice to get an original unmachined head for this – it’s not very good and is poor by the rest of the engine.
               
              Bye for now
              #49272
              mgj
              Participant
                @mgj
                Alan, unless you have a Desaxe arrangement, where the crank is off set with respect to the centre line, port timing will always be symmetrical. The inlet  timing is fairly conservative. One of the limitations of the 2 stroke.
                 
                The 25% oil is probably about right, unless you go to a fully synthetic. You can run these engines right down at 2-4% as long as its jetted for the increase in fuel – with the appropriate oil of course.. These books by people like Westbury, or even Campbell on 4 stroke engines, are very good of course, but they are products of their generation. A  lot of things have moved on, especially oil technology. In fact the change in oil technology is THE thing that has permitted the advances in performance and longevity over the last 20 years or so. You need to know where to lift and where to leave.  Bit like asking Bleriot to give a lecture on aerodynamics.
                 
                 
                It runs – all you have to do is to move that timing plate to get best speed and then back off a smidgen. Slowly reduce oil, and see if it labours, or goes rich.  (do a plug chop, that’ll tell you pretty quick if the mixture is right, or the rice paper test.)
                 
                A 5 is a  cold plug on the Champion scale, or should be if their plugs scales remain  as was. We used to run some of the racers on N5s. If you are running that much oil and you can’t cure the misfire, a hotter plug could well help stop oiling. Any unballasted plug of the right heat rating will do, as long as it fits!
                 
                But at the end of the day its a fifties engine, designed for the crappy props of the day.  Get a nice big prop on it, something suited to todays 90s with a moderate degree of pitch and experiment. (13 x 5?). If you have a hand held tacho, which will be needed for checking the timing, you’ll soon know if you are overloading the engine
                 
                Keep the revs moderately low and it will lug away all day.
                 
                 

                Edited By meyrick griffith-jones on 27/02/2010 22:46:51

                Edited By meyrick griffith-jones on 27/02/2010 22:50:57

                Edited By meyrick griffith-jones on 27/02/2010 23:02:08

                #49285
                chris stephens
                Participant
                  @chrisstephens63393
                  Hi Ramon,
                   I do try to keep an open mind to all advice, but when it does not tally with what I know, I have to ask for confirmation.
                   
                  A memory comes back to me from the days I helped a mate in his outboard motor business. It involves the local boat club’s Commodore’s outboard, it was loosing all power and smoked a bit. Upon stripping it was found that the exhaust system was almost completely blocked with oily crud, from exhaust ports to outlet. When asked what oil/petrol ratio he had been using he quoted the correct one. When asked what oil he was using, replied he had taken the advice of the club’s “expert” that he should not bother with 2 stroke oil and that he should just use standard car multi-grade mixed in with his petrol. This is why I trust manuals rather more  than “hearsay”. 
                  Still, it does take all sorts doesn’t it?
                  chriStephens 
                  #49288
                  Ramon Wilson
                  Participant
                    @ramonwilson3
                    Hi Chris,  Yes it does!
                    A fair comment, based on your personal experience – and nothing a better indicator for making ones own mind up – a factor I totally agree with.
                     
                    It may be that SAE 70 proves to be too thick but at this stage I will take on board what my friends are saying as well as taking note of other opinions expressed. Like so much in life one should listen to all carefully before making a judgement.
                     
                    As I stated quite early on this thread I do not have any personal experience with spark ignition motors but that my intention was to build one. That hasn’t changed and taking an interest in Alans request has spurred me on to do so even more.
                     
                    I guess if I am guilty of anything it’s taking an interest, with my own interest in mind too, in someones problems and trying to help based on the info already possessed on small IC motors as well as, at this stage, as that of others whose experience I know of and value. Turning to such others at  times for info that one is ready to accept but perhaps others won’t is not something that can be foreseen and in all probability you may have similar aquaintances possibly in other fields that you might do likewise.
                    As you say ‘it does take all sorts’
                     
                    I intend to be back with a running example of this old engine too so please be assured that if the oil proves too thick or too much or it doesnt do or live up to what I have been told then I will be the first to admit it – redface or not  
                    At this moment though I would just like to see Alan improve the running of his to his satisfaction and that I at least can get this one to fire.
                     
                    Regards  – Ramon
                     
                     
                     
                     

                    Edited By Ramon Wilson on 28/02/2010 15:53:32

                    #49291
                    Martin W
                    Participant
                      @martinw
                      Hi
                       
                      I make this contribution with little or no detailed knowledge of this type of engine but have a question having had a look at the photos that Alan supplied. The question is, and it will have probably been looked at anyway, can the fuel tank breathe adequately and if not could it be starving the engine of fuel so it can’ rev correctly??
                       
                      As I say this question is based on observations from the photos so I would appreciate it if the more knowledgeable didn’t launch into a tirade regarding my lack of understanding etc!!!!
                       
                      Cheers
                       
                      Martin W

                      Edited By Martin W on 28/02/2010 16:54:12

                      #49293
                      mgj
                      Participant
                        @mgj
                        Could be Martin – hunting which this engine is doing is usually thought of a a sign of being rich, but that’s not necessarily so with a spark ignition.You may well have a very good point. – and I did actually make this suggestion in a pm to Alan some days ago.(about running lean as opposed to a cause)
                         
                        The fire doesn’t go out because its spark ignited, so you get a self regulating effect if the situation is marginal. It sucks and speeds up, runs out of fuel and it slows, the fuel supply catches up, it speeds up. (On a diesel or glow engine of course the thing would have lost heat and stopped.) The thing that made me think that way as the way there was one adjustment and instant death.  Engines running rich tend to become very uneven and stutter to a halt, and having stuttered tend to need to be cleared before starting. 
                         
                        But that  behaviour is very typical of a partially obstructed fuel supply – or of a small air leak in the jet/spraybar assembly.. Also it may run OK, but won’t accelerate cleanly.
                         

                        Still , all will be revealed doubtless

                        Edited By meyrick griffith-jones on 28/02/2010 17:45:18

                        #49295
                        Ramon Wilson
                        Participant
                          @ramonwilson3
                          Having taken another look Martin that’s not an unreasonable question as there doesn’t appear to be a breather vent visible anywhere but that may be well hidden under the cap. Whether that would have the effect of the apparent restriction on running remains to be seen, I would have thought that if the tank were ‘sealed’  the engine would eventually stop through lack of suction. A very small vent eg a crack around the inlet pipe etc may allow some equalisation but might possibly have the effect of causing the engine to run lean as the pressure inside was reduced and richening up as it it equalised however whether that would cause the engine to stop as Alan describes when he moves the fuel needle either way seems to point in another direction.
                           
                          I notice Alan your engine has no webs on the front housing , probably machined off for easier movement on the timing arm perhaps? or just a different casting.
                           
                          Regards – Ramon
                           
                           
                          #49297
                          Alan Worland 1
                          Participant
                            @alanworland1
                            Excellent point Martin about the tank vent – there isn’t one! The only thing I will say in its defence is it runs ‘naff’ from the start when tank would be at atmospheric pressure.
                            I will however try it with the filler removed/loose and see if it makes any difference.
                             
                            Ramon, I never knew the timing can be adjusted by moving the whole points assembly around the crankcase! I have only adjusted the timing by moving the cam on the crankshaft! Not ideal.
                            It does look like where my points are there was a web on the casting which has I guess been removed to enable the points to lay on top.
                            My plug has a 3/8 thread
                             
                            Meyrick, does this sound like ‘hunting’ to you? I have only really experienced hunting on a four cylinder car engine and results in a rythmic increase and decrease in revs accompanied by a sooty exhaust. Mine sounds to me like it is running weak? My experience of 2 strokes not running correctly is when they appear to mis a few ignition strokes and sound like they are ‘8 stroking’
                            I am not sure how this engine could hunt? Surely if the needle valve was unscrewed to allow more fuel in this would mean bigger bangs which would put the speed up and draw more air in?
                            I will have another go tomorrow.
                            #49338
                            Alan Worland 1
                            Participant
                              @alanworland1
                              Had a go today. Mixed up 25% 2 stroke oil with unleaded petrol (same as before) ignition on and started ‘flicking’ the prop with a piece of wooden dowel (easier to replace than fingers!) and it fired second flick and ran for about 2/3 seconds and stopped.
                              Repeated attempts at starting would at best repeat the above or nothing – not even a pop
                              I have found that the throttle if opened more than about 1/4 turn can flood the engine
                              When driving it with an electric drill as in the video it will attempt to fire as there is something coming from the exhaust – but that’s it! most disappointing
                              Ignition sounds most promising when just BTDC
                              I have a nice fat spark in the plug but I noticed as I put the revs up on the drill (plug on bench) that the spark seems virtually non existant above about 2000 rpm – can’t see it anyway? I am now wondering if the cam is allowing the coil ‘on’ for long enough
                              I tried warming the cylinder with a blowlamp but it then seemed less likely to fire?
                              Anyway, gave up, everything covered in oil (including me!) letting it all dry off have a go another day!
                              #49392
                              Ramon Wilson
                              Participant
                                @ramonwilson3
                                Hi again,
                                Alan, further to your oil bound frustration which, I am now pleased to be able to state I can  sympathise with personally, I think I may have found the reason for your engines problems – and almost certainly if the characteristics experienced so far with this example are anything to go by.
                                 
                                I now have this one running successfully albeit not on spark ignition – that is the next stage – but I thought you and others may be interested in progress so far.
                                 
                                In order to ascertain whether this engine would run at all I decided to take onboard the advice of Hugh, who is, after all, well experienced in running petrol engines and does, to be fair, actually practices what he preaches but first I took another really good look at the various engine parts and it’s make up beginning with the carb.
                                 
                                The needle has a (relatively) coarse thread and taper and it was felt that this is probably the root cause of the ‘rich’ fuel situation which, for this example certainly, has proved to be.
                                 
                                The piston does not have a transfer port in the skirt so could be fitted the wrong way and it would still run though probably nowhere like it should. The transfer port is cast into the crankcase and connects directly with the main cavity. However this is only a possibility and not likely to be the cause
                                 
                                The timing was checked with a timing wheel and shows the exhaust opening for 100degrees the transfer 78 degreesand an inlet period of 76 degrees.
                                 
                                Before any running could take place a simple cylinder head to take a glow plug was made the internal shape simulating the original with no attempt to reduce compression. Indeed I would think given the quick method of producing the shape it is possibly very slightly higher.
                                 
                                A propellor driver and brass collet were made but this would not grip as it had nothing to push back against on the 5/16 dia parallel shaft. The front housing was bored out to take a larger phos bronze sleeve and the crankshaft diameter increased with a high carbon steel sleeve loctited on and then turned between centres to a running fit.
                                 
                                Using standard 80:20 Methanol/Oil glow fuel the first attempts at starting showed a total impossiblity to control the fuel flow from the crude needle arrangement the engine simply flooding and refusing to start.
                                 
                                A simple venturi was then turned up from ali with an increase in the bore size to 6 mm and a slight 8 degree taper in the inlet end. A basic 3mm dia spraybar was made with a much finer thread and needle taper. Whilst the bore was increased the choke area is possibly slightly smaller than the original (Visual comparison)
                                 
                                At this stage these are the only alterations to the engine – one a practical need
                                (crankshaft) the other an improvement on fuel supply. I really do not think the original ‘carb’ is up to the task – certainly for glow and which will probably be the same for  petrol.
                                 
                                The compression with the new head is good but not excessive and the piston seal likewise. After quite some flicking (I have never used a starter) and some finger biting ‘pops’ the engine began to fire intermittently before running – I believe – in an identical fashion to yours. (It certainly sounded the same) Thing was it took a few seconds for the penny to drop. It wasn’t actually running! but merely oscillating – firing alternately back and forth quite happilly.  Gradually closing the needle (about 31/2 turns open) a few degrees at a time  the engine suddenly gave a couple of burps and burst forth into a free and easy run albeit backwards as side ports will do. The finning on this engine is ‘marginal’ to say the least and with that solid head it was difficult to keep cool but I have had several runs today like this oscillating at first followed by running ‘properly’ in either direction two or three minutes at a time. Like all lapped piston glow engines though virtually impossible to hot start so plenty of tea breaks!
                                My old analogue tacho, languishing in the model box unused for several years is typically now not working but I would hazard a guess about 4000 or so on a 13 x 5 Zinger wood prop. I hope for a loan of one so more on this later.
                                 
                                Now whether this is happening to yours given the need for a spark at the top of each stroke I don’t know but the similarity in sound  as well as visual appearance to your video is striking. I’m sure you realise Alan but I’m not saying this is what is happening to yours merely my observations on this one but it’s probably worth another look. Its easy enough to spot though by the difference in draught from the propellor – virtually none whilst oscillating but a good breeze – forward or back otherwise!
                                 
                                Based on todays experiences then my opinion at this stage is that the fuel system delivery is definitely critical to this engines make up. The second half of Hugh’s statement ‘if it will run on glow it will run on petrol’ is yet to be proved but so far, with the first half out of the way, I feel I’m on the right track.
                                 
                                If you are not able to follow the same path regarding making parts then once I have (or not as the case maybe) got it running as intended then you are more than welcome to these bits.
                                 
                                #49393
                                Ramon Wilson
                                Participant
                                  @ramonwilson3
                                   
                                   
                                  If you are not able to follow the same path regarding making parts then once I have (or not as the case maybe) got it running as intended then you are more than welcome to these bits.
                                   
                                  And so now to discover the delights of ‘spark manufacture’
                                   
                                  Regards for now – Ramon
                                   
                                   PS I have taken some pics as well as some ‘video’ on the still camera.
                                   
                                  I’ll try to get them posted later.
                                   
                                   
                                   
                                   
                                   
                                   
                                   
                                   
                                   
                                  #49395
                                  Ramon Wilson
                                  Participant
                                    @ramonwilson3
                                    Hi again
                                     
                                    These pics are taken retrospectively – it appears I deleted the ones previously taken when running the engine!
                                    So, for those who have an interest –  (grannies of course – the usual).

                                    Shows the increase on shaft dia, collet and prop driver. The cam is the original.
                                     
                                     
                                    Just about shows here no piston port and the long (and large) transfer passage

                                     
                                     
                                    Checking the timing
                                     
                                    The two heads – the depth is the same but the original is sligthly more concave.
                                     
                                    The parts for the intake tube and spraybar. The needle is .048 piano wire the needle thread 8BA (mild steel studding drilled through) The cross hole and the hole the needle seals is .037 dia
                                     

                                    Unit assembled – Knurled part is a locking nut

                                     
                                     
                                    These last two were taken in an attempt to try to capture the difference in oscillating and running (in case the video doesn’t materialise  – I haven’t used that before) They don’t really capture it but the first is when the oscillation is occuring the second after it has cleared  itself. The only indication is the prop and I accept it’s not particularly convincing . I will now try to get that video sorted then!
                                     

                                     
                                     
                                     
                                    #49405
                                    Alan Worland 1
                                    Participant
                                      @alanworland1
                                      Crikey you have been busy! Thanks for your efforts.
                                      As you have probably read in my post my throttle is VERY sensitive – about 1/4 turn open is probably what I had it running on previously
                                      It was definately running, I have not experienced an ‘oscillating’ condition – looking at the crank end I have had it running anti-clockwise. I know it will run both ways but the prop I had required that running direction.
                                      With your new carb fitted were you able to control the speed of the engine at all?
                                      As I had ‘oiled up’ the plug several times on removing it for cleaning I checked it for spark by laying it on my metal topped bench and as I have said previous with increasing revs there seems to be a reduction in spark – I am convinced there is insufficient time allowed on the cam to energise the coil properly, I am interested to see if you find similar.
                                      What sort of current does a glow plug draw? I believe they work from 1.5 volts?
                                      I will probably have another go tomorrow – glutten for punishment! I use a piece of 1/2 inch dowel to flick the prop but after my last experience I feel my finger would be quite safe.
                                      #49406
                                      Ramon Wilson
                                      Participant
                                        @ramonwilson3
                                        Hi Alan,
                                        That’s interesting you are sure it wasn’t oscillating. I’ve seen it before on small engines diesels in particular when it can sound quite ‘rough’ but never as smooth and as ready to run as consistently in the state as this one was today! so I guess we need to keep looking then
                                         
                                        I’m still convinced this is a fuel/air problem possibly coupled with internal distribution. Your description was the problem I found – just a mere crack of the needle was sufficient to bring about a flooded state. The system made is much better at controling the fuel and it will run over a good turn or more. Screwing it in gradually leans it out, the rpm increasing and the engine note becoming smoother. At this stage though cooling, or rather lack of, becomes a problem, those fins are so marginal, there isn’t really much material (even on that original head) to dissipate the heat and the engine soon loses its seal until it cools again. It isn’t labouring at all but it definitely prefers a richer mixture to aid cooling.  That is not to say it’s being leaned out to such an extent as to cause overheating – like yours it’s new – virtually unrun so that is not an option as yet. The newness is born out by the crankpin. It is in very slightly ‘on the huh’ sideways (looking down on it at TDC). This has caused the bronze big end bearing to deposit on the pin – something there was no evidence of when initially stripped down but this doesn’t appear to be having any apparent effect on the running as yet. Despite this newness the engine flips over very easilly – no sign of any tightness at all at any point.
                                         
                                        Having now established that it does indeed run I shall now get on to the spark side. I have read up as much as I can from what I have been able to obtain so far on engines of the period and most describe the cam as fitted as the norm. But like you I can’t ‘see’ at the moment how that short closed period allows sufficient time for the coil to work. It will probably be next week before I will be able to get back onto it. I just hope the coil and condenser I have are serviceable. I certainly don’t want to think about electronic systems at this stage though there’s no doubt they seem to be much more positive and reliable. 
                                         
                                        Glow plugs can be 1.5v or 2v. A 1.5v can easily burn out on a freshly charged 2v battery.
                                        and the 2v don’t work too well with the 1.2 v rechargeable type self contained glow plug ‘starters’ if the engine is a bit of a recalcitrant one (This is all hand starting of course)
                                         
                                        A rubber sheathed wood ‘chicken stick’ isn’t a bad idea, I did get a few raps on the back of the fingers today – occupational hazard? – but I really don’t like those thick rubber finger protectors as you lose all feel of the engine. A good stout leather gardening glove is what I use – doesn’t stop the occasional whack but the fingers are still all here!
                                         
                                        The video transpires to be slightly disappointing in that it doesn’t run for long enough – a non modelling friend was taking it for me and the camera only has a couple of mins recording time. The big problem though is that so far I have been unable to transfer it such that I can post it. I will work on this though and see if I can get some better coverage and with luck actually get it on here.
                                         
                                         
                                         
                                        #49415
                                        Circlip
                                        Participant
                                          @circlip
                                          One thing you COULD try Alan is posting on :-
                                           
                                           
                                           With the best will in the world, getting info from third parties twice removed really confuses the issue.
                                           
                                            One reason for using a sparkie in toy boats was that they were slow revving but had bags of TORQUE so the howl of a glow type hadn’t been invented. The “Oscillations” syndrome was usually induced in toy Diesels by trying to run too rich so you got a sloppy sound when flicking over with a naked finger.
                                           
                                            As you’re “Wimping out” () by using a starter, this is hard to believe that it’s “Four Stroking”.
                                           
                                            Keep taking the pills.
                                           
                                            Regards  Ian.
                                          #49434
                                          Alan Worland 1
                                          Participant
                                            @alanworland1
                                            Great website Circlip – thanks
                                            #49548
                                            jomac
                                            Participant
                                              @jomac

                                              Hi, just a few thoughts. while I was turning up some cylindical squares.

                                              First try reducing the oil ratio down to 10%-12%, it seems to have an excess of oil or fuel dripping out of the exhaust, that could be put down to a bad air to fuel ratio,

                                              Second idea, is that in the early years small manufacturers had to cut costs some how,

                                              Getting the machineist to make there own needles was expensive, so was buying box’s of sewing needles, but there was a big supply of gramaphone needles, unfortunately most makers had different shaped profiles and tapers,So if a hobby model engine maker took one off there own record player, it was a hit an miss affair, The other problem was that 50 years ago, small drills were not the same strength and quality that we have now, and if the home machinist had a worn or badly sharpened drill, if drilled from the needle side of the tube, bell mouthing could occur, As an example put a washer over a morse taper, pull it back, say 20mm and see what the air gap is, then put it in another morse taper, pull it back the same amount, and you will see a much bigger air gap. coupled with a miss matched needle, you now have a hard to tune engine.

                                              So, make a selection of needles of varying tapers, clean up the needle seat, and see how that goes.( MEN has articles on makeing needles and tubes), You need a combination that will allow the coarse needle adjusting screw on your engine to work properly, ie, at least two to three turns of the screw,to get from from low revs to nearly full rev.

                                              I saw an article on making needles, useing the right diameter piano wire, just by fixing one end solid, using pliers or a rod, on the free end and then  heating the the section to be tapered,with a gas burner pulling and stretching the wire to get the right taper, then cutting out the section you needed.

                                              Hope this is some help.

                                              John Holloway

                                              #49567
                                              Alan Worland 1
                                              Participant
                                                @alanworland1
                                                Thanks John – there is obviously something very wrong in the needle department as it was so critical on setting, when it did run virtually any adjustment of needle would cause the engine to stop. Looking at the needle it does look quite ‘blunt’. Could be worth re-engineering this area.
                                                My last attempt at getting it to run was very dissapointing – it didn’t! A few pops here and there and that was it!
                                                As it was again very oily I dilluted the petrol mix by about 50% (making about 12%) but it didn’t make any improvement to starting.
                                                Although in the video it was not running properly at least it would start and run on demand, I don’t know what has changed – at the moment it is just an oily paperweight!
                                                #49568
                                                Alan Worland 1
                                                Participant
                                                  @alanworland1
                                                  Thanks John – there is obviously something very wrong in the needle department as it was so critical on setting, when it did run virtually any adjustment of needle would cause the engine to stop. Looking at the needle it does look quite ‘blunt’. Could be worth re-engineering this area.
                                                  My last attempt at getting it to run was very dissapointing – it didn’t! A few pops here and there and that was it!
                                                  As it was again very oily I dilluted the petrol mix by about 50% (making about 12%) but it didn’t make any improvement to starting.
                                                  Although in the video it was not running properly at least it would start and run on demand, I don’t know what has changed – at the moment it is just an oily paperweight!
                                                  #49569
                                                  Frank Dolman
                                                  Participant
                                                    @frankdolman72357

                                                         My silly question for today:  has your battery gone flat?

                                                    #49570
                                                    Frank Dolman
                                                    Participant
                                                      @frankdolman72357

                                                           My silly question for today;  has your battery gone flat??

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