120 L-Drive has no spark. Was running good, but hard to start a few times. Never shut off - just a no start at times. Now it won't start at all. My Clymer manual says I have Prestolite ignition, but I have Thunderbolt ignition, so I can't trust troubleshooting. Does anyone have specs on resistance/voltage tests for this sytem? Any help is appreciated! Randy<br />