No start 71 911S: ignition question

[Wolff1953]

I pulled the rotor out while on vacation to deter any car thieves. When I re-installed the rotor, carefully snapped the dist cap in place and tried to fire it up = no start (1st time in 9 yrs).
Fuel check: There's gas in the tank, heard the glug glug of the fuel pump when the igniton was turned on, strong gasoline smell in the exhaust after spinning over the motor
Ignition check: I get the Permatune whine with ignition on, rechecked seating of the rotor, rotor points and dist cap are <2000miles on them and all ok.

My question: As suggested in several threads, I pulled a plug wire and attached an old spark plug to it and held it near a ground point while truning over the motor. I saw a single spark when the ignition was turned on but no spark while the motor spun. Is the single spark normal and/or what does it indicate about the distributor, lead primary wire, etc. Hope you can help! Thanks.