Then ít gets cancelled for weather, then you try to get back on the schedule in maybe 6 weeks. I know this because my son had this happen in last 3 years. Private twice. Instrument twice, commercial 3 times.
When I was flying a jump plane 182 many years ago, I remember at 500 feet reducing rpm by 100. But, throttle stayed wide open till altitude was reached usually 7500 feet.
It's there, then, on front of engine, pilots side, below propeller hub.
https://www.rapcoinc.com/images/vacuum%20pumps/RAP215CC-9.gif
Have you seen this?
https://150cessna.tripod.com/oilflow.html