New to this forum so please be gentle with me if I am posting in wrong section. Currently 'locked down' in France (Covid-19) so away from my UK base and struggling with a Countax C600H ride-on fitted with Briggs 16hp Vanguard engine. To cut an extremely long story short I bought this mower s/h about 2 years ago and it had been built, I think, from several different 'donor' mowers. However, it wouldn't start on the key so I bought a new ignition switch. Still no joy, only started when shorting out solenoid so did that for a while then about a month ago I decided I should get to the bottom of this. This mower has safety switches for the safety switches and a printed circuit board for the ignition circuit. After lots of different attempts I decided to disconnect all the loom including the pcb and just wire up the engine as though it was in a go-cart or something. It now spins over like a good-un but won't fire. I've connected the fuel solenoid to the spare terminal on the ignition switch and that works. I've disconnected the 'kill wire' loom as the diodes are visible so they may have burnt out, still no good. Found that one plug lead had been chewed by a mouse (found the corpse by the flywheel) but only the outer insulation. Getting a spark, left or right but never at the same time and never reliably - i.e. sometimes one will spark but not the other and vice versa. Also, the plugs are always dry. New fuel filter fitted, cleaned out carb bowl (which was full of fuel) and am now at my wits end. The grass is growing, I have arthritis and cutting half of the grass with a push along petrol mower has put me on my back for two days! Can anyone help please? The ignition switch has M, S, B, L and G terminals. I have connected M to the charge wire coming from the magneto. B to the battery, S to the starter solenoid and L to the fuel solenoid.