I wouldn't be just trusting the castor oil in your fuel... Maybe it is because it is so humid in Queensland during our summer but in the past i have still has rusty bearings.
Castor oil is a bit sticky and does not attract moisture, it will create a perfect airtight seal on the metal parts. Castor has a negative thing that it will dry out. It can block the needles and lock the piston if it is not used for a long time. A good afterrun is made of an oil that will not dry out.
Both main ingredient in our fuel NitroMethane and methanol are hydroscopic and attract moisture causing rust.
Last edited by Bundy_Bear; 08-29-2017 at 03:57 PM.