My mower started backfiring, ran ok for a while, then quit. Crank no start. I had no spark, and found the coil module to have no resistance and replaced it. Still no spark. the part people said to get the spark advance module, replaced, no spark. I traced to a bad relay, replaced and now I have spark. Still no start. Seems to get fuel as plug will get wet with gas. Terrible muffler bang or backfire into carb throat when using starting fluid. Checked for flywheel key and it is ok. I did notice that the magnet for the ignition is almost 90 deg off from TDC. Is this normal, or do I still have a bad spark advance module? Or something else, internal?