I have a perfectly running Brison 3.2 that has been changed to electronic advance using a CH module. The timing has been set to 28BTC in accordance with Milton’s video. A Smart-Fly kill switch is between the ignition switch and the module. On occasion the engine kicks back on start up and backfires and then won’t start at all. I have changed spark plugs and ignition modules to no avail. I have rechecked the timing more than once. It usually happens after about 6 eight minute flights and the engine has cooled off. The ignition battery has plenty of capacity and always measured strong under load. A starter will get it going. This has been happening to two of the same engine, ignition combinations. The next thing I am going to try is to bypass the kill switch and/or change the sensor. Any other ideas? Are these symptoms typical of a timing problem?Dan.