MISSFIRE WHEN WARMED UP

Posted by Denny Z On 2009/6/9 20:21:40

I tuned my '41 Clipper (new plugs, wires, points, condenser) and she starts on the first crank and runs smoothly . . . until she gets warmed up. After maybe 10 miles she begins to run rough; I think I'm loosing at least one cylinder, maybe two. I've rechecked the plug wire connections and they seem fine and they all snap when connected to the plug and cap. Could I have a bad plug, or could the gaps be ok when cold, but incorrect when warmed up? Help!