do not EVER, EVER use 2 cycle or any other petrolium
based oil on a water pump impeller. This will
destroy the rubber in no time.

Are you sure?
I think that impellers for positive displacement pumps are made of high
quality oil-resistant synthetic rubber, not of fragile latex used in
condoms.
In every aircraft, hundreds of rubber parts bathe happily in cold naphta
fuel, hot oil and hydraulic fluid!
If in doubt, use electronic silicone paste, silicone oil or brake cylinder
grease but not KY Jelly, it is a water based Sexual Lubricant and it is
useless in machinery applications, it simply dries after half a hour.
Regards, Tadeusz