Collection, Preservation and Display of Old Lawn Mowers
I don't know if this will help you but it certainly helped me with a Villiers on a British Seagull outboard I restored recently. It took a minute or two but then the spark suddenly came back strong as ever...
Interesting but I’m not sure about the science. One non scientific observation is that spinning with a drill gives immediate and consistent higher rpm than that achieved with the rope wrap pulley. It is also considered poor workshop practice to spin the mag with nowhere for the spark to go . Doing that can cause the spark to jump between the HT windings of the coil - particularly if it’s “ on the brink” and cause internal tracking which will destroy the coil. Old Villiers coils could often be observed with the spark jumping out of the back to earth, even with an HT lead and plug connected.
I would be happier with a proper condenser and coil test, particularly the condenser, even if new. Also, the only way to clean points properly is with them removed from the stator. I use a small fine grain carborundum slip stone to remove any pips or pits. It is also important that the points close with their faces square to one another and not lop sided.
Electronic trigger modules have their uses but are not a magic cure for a dodgy coil , and do tend to demand slightly higher cranking rpm on the starter.
Old engines need to be as good as you can get them. You may have to live with a worn bore but there’s no “ excuse” for less than perfect valves an seats , accurate ignition timing and the correct plug. However playing with the plug gap may be beneficial.
A bit of progress. I have found another FO7 engine that works but the shaft is nit shamferred to fit the Ransomes Clutch Drive.
I have taken the electrics complete from the working engine to the non working one and beleive it or not it dosen't work.
So tried the old electrics on the new engine and it sparks though I haven't tried starting it yet.
So I might have two electrical systems which don't work on the engine fitted to the "Fourteen"
Still got to try out and puzzle what's wrong.
Thanks for your suggestions
I think I'm beaten. Both electrical systems give a good spark on the engine that's no use to me and neither work when fitted to the engine I need. All live wires are insulated and not earthing as far as it is possible to see and all earth wires earthed.Can only suggest someone has put a curse upon it.Looks like the scrap heap for the machine not me.
Are they working with their own flywheels or is there one working flywheel and one not?
Can you trim your last post - there are acres of empty space !!
Don't seem to be able to get rid of the white space.
Anyway I have tried both Flywheels on both engines and same result.
White space removed.
F07 - is that what is usually referred to as one of the Villiers Lightweight family - 75cc?
So, as I understand it you have two mags that work on one block but neither work on the other block? Can’t quite get my head around this, always easier with the metal in front of one but there has to be a difference between the two engines.
When either of the working mags are fitted to the non working block have you checked the points opening against the piston and valve positions as opposed to any existing timing marks?
No. I hadn't thought of that, I'll try that as soon as I get time to get back to it, probably tomorrow, Cheers
Certainly a good idea to rule out any timing issues between the two engines but unless I have misread it the problem is no spark when either of the ignition units is set up on the troublesome engine. There has to be a reason for this happening but as wristpin has said it would be much easier to trouble shoot it with the lump in front of you.
Now for a completely off the wall suggestion - when you next check for a spark on the bad engine try earthing the spark plug onto the magneto back plate rather than against the cylinder head, if you then see a spark you need to check for a good electrical connection between the magneto backplate and the engine block.
As per Hillsider’s suggestion, off the wall problem requires an off the wall answer, so here is another question. Are you trying it without the engine cowling in place? If so the cowling could be the missing earth path as per Hillsider’s suggestion. Never come across it but we’re running out of answers.
Thanks to both of you, I'll try out your suggestions, I think the timing is OK so your alternative suggestions are very welcome as I have completely run out of ideas.
Will post a reply after I've tried them possibly tomorrow,
Right Gents, let me recap, this is the ongoing saga of two engines, a green one and a red one, both F07 engines, the green one older than the red by a year or two.
I need to get the Green one going and only need a spark (the red one is of no use to me as the Crankshaft is slightly different in dimensions and I can't fit the green crankshaft in the red engine.
The red engine gives a spark when both it's own and the green engines magneto is fitted but when either magneto is fitted to the green engine neither give a spark.
I have tried all combinations and tried your off the wall suggestions and still no luck. I have tried them both on the work bench and on the machine with the same result.
I have taken quite a few engines to bits in my time and got them working but am no expert having only been a user of such equipment and not an engineer nor a scientist. However logic says that the Electrical parts are OK and it must be a fault on the green engine but I can't fathom what it is.
I attach a few photos which won't I'm afraid tell you much but you will be able to see the parts of the red engine first then the green.
Not very good at the technique of adding photos so please make allowances.
Photos are as elusive as the sparks!
Has the green engine ever run in your ownership?
Yes for a short while after I got it, before it blew the head gasket which was a home made contraption. The gasket blew because one of the head bolts wouldn't tighten up but I have now helicoiled it and fitted a new gasket. At the same time I decoked it and checked the valves which were in good condition and well seated.
Sorry about the photos as they looked as though they had uploaded. Never had a lot of success with photos on this system but they seem to upload OK to Ebay.
Question - if both engines are the same why can't the crank be swapped over to the sparking engine?
I realise it is a lot of extra work but it could prove a point and give you an engine that runs. I can't help thinking though that something is being missed in the way that the parts are mounted on the engine.
Photos. Different system from eBay and most other forums ! BUT if you follow the sticky it does work.
When photos are uploaded but not showing in a post this is invariably because the user has not clicked the INSERT button next to the uploaded image.
This step is clearly explained in the instructions on the editing page.
It happens quite often but I'm not sure how I can make the process or the instructions any clearer.
When I find a page where this has happened I can usually make the images appear, as I have with the post above.
One of the many advantages of the system underlying the website is that you can choose from a variety of image sizes to show with your post.
Hi Hillsider, Although both engines are superficially the same and both carry the F07 identification mark, when you strip them down the counterbalance on the crankshaft of the older machine is about a quarter of an inch larger than the later engine and there is not enough clearance in the crankcase. I tried the exchange a while ago as a way round the problem.The only other solution would be to grind the driveshaft end of the crankshaft down to a taper if this is possible but I don't have any kit to do that.
Thanks for your continued interest.
Good News!!!!!!!!!!! I have a spark.
One last session before I was to give up and I get a spark, not too strong but a spark.
Dismantled everything cleaned and put back together- nothing then tried every combination of gaps in points and plugs (three plugs two brand new and one old L10) - nothing. Sprayed the lot with WD 40- (stupid?)-nothing.
About to have my tea and started to think off the wall like you guys suggested.
Back in the early sixties in the back woods of North Yorkshire as an under gardener on a private estate, we had a number of two stroke Atco's which were notorious poor starters and I remembered the old dodge of using what we called a lead pencil in those days(Carbon) scraped across the spark plug points which sometimes worked.
However, not expecting any different results than before I was pleasantly surprised to get a weak spark.
I'm not getting too excited as this was on the bench and I haven't put the engine back on the machine but I'm hopeful.
Thanks to Hillsider and Wristpin for your ideas it does help when working in isolation, worth being member of the club to have contacts with such a wealth of experience.
Progress indeed. I don’t see why you should loose it just by refitting the engine to the chassis. Out of interest is the spark as good as you had on the red engine. I’m guessing that red is BSA and green Villiers? Also, have both flywheels got the same magnet arrangements ?
Flywheels are identical and spark looks identical. Have reassembled the red BSA and it's working fine. Still got to put the green one back together and fit to the machine, fingers crossed.
Werll good news, engine back on machine and it runs perhaps needs a fine tune yet, but can now do a few modifications as fuel tap is rubbish and leaking and Grease nipples for cutting cylinder missing, broken throttle lever etc, nothing which can't be easily fixed, then a bit of painting up and hopefully I've got a usable decent though old machine.
Well done indeed, shows what a bit of perseverance can achieve, good luck with the fine tuning..