What Sean said. Clean up the coil and magnets with fine sandpaper.
The kill wires in the back of the carby aren't installed correctly (First photo). That could easily be killing your spark. Make sure the first wire (Fits straight into the carby and is moved by the cam inside) has a new rubber boot on it and the kill wire that slides in the side (The one you can see in the photo) fits nicely in one hole and out the other. If you have never dismantled and reassembled a G4 carb get on youtube and search victa g4 carby. There are a few good videos that will show you how to do it.
Short of that I cannot see anything you need to fix. Have you checked the points gap? You will need a feeler gauge (Again if you have never checked a points gap search youtube).
Let us know how you get on.
Pete
