Since it fires on starting fluid which takes less energy to light up than gasoline, I'd go throught the igintion system. This is even in light of the reference to your good spark on cylinder one. There is a lot more resistance across the plug gap in the cylinder with pressure and gasoline vapor and air. Check the rotor and distributor cap. The coil could be weak. The plug wires or coil wire could be a high resistance path. Replace the plugs if over 35,000 miles unless platinun or iridium. jp