I just ran across something last night that sort of tossed me off balance a little. I was setting the timing on a couple of engines, RCS and Brison. The ground wire slipped off yet I was still getting spark. I never tried to time an engine without the ground connected before and always thought the ground wire had to be connected or the plug wouldn't fire?? I went ahead and pulled the ground wire off the other engine and rolled it over, the spark was just fine on that one too. Is this normal?? I have been doing this for years but it's the first time I have ever noticed this.