My normally aspirated O-320  has an electric primer, so the pump must be
on for that.  (I quit using the throttle as a primer after a friend
nearly lost his RV4 to an air-box fire after using the throttle.)  After
start, pump is off through run-up (so the mech pump gets checked),  back
on for takeoff.  Off when clear of the field.  (I would occasionally
forget this in my Grumman and leave the pump on for the entire flight -
so the Lancair has a green tell-tale light for the elect pump.)  Pump
back on prior to entering downwind, off after clearing the runway.

Dick Alden
LNC2 (320), N425A