Yup - seen THAT before...
... and for NOW:
Re-assembled, with gear oil on the eccentric, and grease on the end of the armature shaft WATCH FOR A WASHER ON THE END OF THE ARMATURE SHAFT.
(AND THIS IS THE
GOOD STUFF)
Pump lid NOT sealed yet...
bench (tire

) test dialed in (jumped straight from battery - more on that momentarily here)
vac nipple blocked; switch killed pump right away
and this question, about vac test without plenum re-installed, is answered
cables run to P side fenderwell, jumpers on vac pump (never mind the Guinny Stoudt - NONE for you! )
This juncture shut off right away, and held
reservoir evacuated in 3 seconds and held
