I've been meaning to do this for a while now so with no other lantern related projects on the go I went ahead and did it. 1. Remove the old generator. 2. Grind off the flared end and remove the jamb nut. 3. Replace the generator for a 639 model. 4. Add a pre-heater cup 5. Reassemble everything. 6. Fill tank with kero 7. Fill pre-heater cup with meths and light. 8. Wait until meths is almost used up. 9. Open valve and away she goes! Apart from the potential safely issue with the Schrader valve when it eventually needs a new o ring, I have 1800 litres of kero in the central heating tank at any one time and it costs 50p per litre. It's a no brainier really, especially as the new heating fuels are now low sulphur.