A lot less than your Civic, that's for sure. The last time the engined idled for a long period of time was in November 2007 (Pretty close to the date I posted that). We tried to start the engine in May 2009, but the noisy thing fired only for a few seconds.
The main problem is the ignition coil, then, the carburetor is jammed (I don't know HOW THE HELL did that happen). But even if it ran, I would rebuild the engine anyway. When my dad used it years ago he often had to pour oil in it, which means old piston rings or valve seals, whatever.