Flymo GT2 / JLO Engine / No Spark

[aesmith]

Hi,
I have a Flymo GT2 with the two stroke "JLO" engine, I have no idea how old it is. Last weekend it cut out soon after starting, and it is giving no spark at all. I haven't yet rigged up a puller to get the flywheel off, so all I have been able to check is that there is continuity in the high voltage side (a few thousand Ohms) and the low voltage side (a few Ohms).
Does anyone have any background information on how the ignition system works on these? Looking through the openings in the flywheel there doesn't appear to be a contact breaker, there are just a couple of black boxes and what looks like a capacitor.
Any suggestions welcome.
Thanks, Tony S

 

[Burnerman]

If there is a contact breaker then you will be able to see it through the flywheel openings - although working on them will be a little more difficult!
The black boxes will be coils, and the capacitor could indicate a contact breaker.
Pics please, if you can!
To shift the flywheel, can you lift it up and down just a fraction? The larger JLO motors had bolt extraction holes but I can’t remember this one. If you can lift it a bit, do so after shifting the flywheel nut......wedge it and strike the end of the crankshaft ( nut loosely back on) sharply.
John

 

[aesmith]

Thanks. I'll get pictures. The flywheel has a fine thread inside the well where the nut locates, but it also has three M6 (to be confirmed) threaded holes as well. I think those would be easier to use for an improvised puller. I did try thumping the nut as you suggest, maybe I'm too scared of damaging it.

 

[Burnerman]

That fine thread is to accept a kosher extractor - there are many diameters though so you can't guarantee a 'universal' one.
If you use the 6mm holes, beware of the screws damaging anything inside the flywheel. The flywheel nut may need many thumps before it budges so be lucky with it!
John

 

[aesmith]

I've had a chance to have a look, and taken a few photos with the flywheel in place. I think the thread for extractor is 1.25mm pitch, definitely bigger than 1.0mm. Inside diameter is 24mm. Not sure where that leaves me, 24mm is the tapping drill size for 27x3mm thread, but this isn't 3mm pitch. I haven't found data for larger fine threads yet.

Before splashing out on a puller, even if I can find one, she has suggested I try a new sparkplug. She's been correct before so after initially dismissing since I tested direct from the HT cable, I think I'll try that anyway.

Here are the pics ..

Now pictures through the openings, in some cases shining a torch to try and see the innards. I can't see anything that looks like any sort contact breakers I've seen before. The device with three wires attached might be a condenser with one of the three cables being for the cut off switch.

 

[Burnerman]

I think you are going to have to persevere getting that flywheel off somehow - on your second from last pic there could be some sort of adjustment for a contact breaker just visible?
You can never replace points without the flywheel off - but you can always adjust them with the flywheel on.
John

 

[Burnerman]

This is the sort of thing you could be looking for:

Engine Magneto Flywheel Puller Repair Tools For Motorcycle V3A9 new F2G0 J9K | eBay

1 Engine Magneto Flywheel Puller. You can follow below process to chontact us. Suitable for most scooters and motorcycles. 24mm screws are suitable for GY6 50cc 60cc 80cc DIO 50CC. All pictures are for illustration purpose only and Colours may vary slightly.

www.ebay.co.uk

One diameter is 24mm - not sure about the thread pitch though!
John

 

[aesmith]

Cheers. I see what you mean about that screw in a slot. There's another on at 180 degrees so it looks like something to adjust the whole back plate ..

Regarding the thread size, my take is that if the internal diameter is 24mm (actually it's a touch more) then it's bigger than M24. In the same way that the hole in an M16 nut is 13.5mm or so, not 16. I just don't know what size.

 

[Burnerman]

JLO are German and Austrian made - I do know the common extractor sizes are 26mm and they fit Honda and Lambretta etc, 24mm often for Chinese kit. Maybe worth a gamble, or think of a way of utilising those 6mm holes.
I’d still pop the nut on and give it a good thwack though!
John

 

[aesmith]

Had a proper measure of the internal thread, it's 1.5mm pitch not 1.25, so it looks like an off the shelf puller might work. I have seen 26mm in 1.0 or 1.5mm pitches.

 

[Burnerman]

For sure, your flywheel has the larger pitch- I have the 26mm fine pitch one.
John

 

[lostinthelight]

You may get a 3 leg puller in the FW cutouts if you can get them in a position that clears the workings