Engine built about 2004. When running, if I turn off the ignition, or pull the kill cord there is no effect. Have checked by grounding white wire from CDI and that stops the engine, so it's unlikely to be a CDI failure. Have run a new wire from ignition + kill switch to ground on the engine. That tested ok and ignition or kill both stopped the engine. But when all connected up for permanent use it worked once then didn't. AVO meter along new wire shows it's conducting current. Any suggestions for what to try next? I can follow recipes but please don't get too technical.