Update-The air leak is gone. Probably in the test setup. I have cleaned the carburetor, changed to new high octane fuel, cut 3/8" off of rear ignition wire at spark plug cap. Normally, the forward cylinder is the only one working. If I leave the forward spark plug cap off the rear cylinder works, but they are a bit finicky trying to start on one cylinder. With a cap off, the engine will only hit 4650 RPM. I took a video of the two spark plugs firing outside the engine today. I need to put the video where I can slow it down, the starter cranks at 1000 RPM and looks like both plugs are firing the same time. One plug should fire 180 degrees after the other. My Owner's Manual theory only explains single cylinder. There must be a component in the magneto, coil, or somewhere else that puts the spark on the second plug 180 degrees later. Anyone know what this is called and where it's located? Also, I'm unable to pull the spark plug wires off of the coil. Are these ever hard mounted into the coil? After I slid the sleeve away from the coil, several times I pulled 40 pounds and it didn't budge. The forward cap is real simple with the inside composed of a bent uninsulated splice, which doesn't positively snap onto the spark plug. The rear cap says NGK, is 5000 ohms and provides a little brighter spark that doesn't fade out as quickly as the forward one. Each spark plug, without changing position on the coil, will run either cylinder if I leave the other cap off.