I've been in a similar situation when arriving on an oil rig to start a job (drilling out in 2 hours ; next helicopter on 3 days ; no spares on board, see further comments below about manuals). The pneumatic motor for extracting gas samples hadn't been operated for 4 months (contrary to rig-up instructions ; I wrote the manual and definitely put weekly runs into the mothballing procedures ; they weren't followed but that's a separate issue).
The motor wouldn't start by jagging it (power/ air on and off repeatedly). Still wouldn't start after filling the inlet line with lube oil and jagging it (this is what the weekly runs in the "mothball" section of the manual were intended to achieve).
Final solution, which got it working, was jagging it while tapping with the shaft of a hammer on the visible bearing housing, in the direction of the shaft. That put enough vibration into the bearings that the applied force from the air (and lube oil) on the motor vanes started to shift the vanes by a degree or two ... which exposed one of the vanes to fresh lube oil ... which reduced the friction. 10 minutes of doing that every few seconds and the motor started to turn, slowly. After that, the lube oil did it's stuff.
I fucking hate people who don't READ the fucking manual after I've gone to the effort to WRITE the damned thing. Do they think I'm typing for the good of my fingers, or something?
The same trick will often work with a stuck bolt or gas fitting : apply spanner in the undo direction (and CHECK if it's left or right-hand thread !! We have enough L-H threads that you learn to check, but now you can't claim you weren't warned!) and keep a steady pull on it ; hit the head in the direction of the bolt shaft repeatedly while keeping hand tension on the spanner. Easing oil helps (not fucking WD40). Spending 20 minutes like this is better than having to deal with a sheared-off fitting which invalidates the Explosion-Proof rating of the enclosure.