Also,
ether is required for the castor oil to mix. Diesels require castor oil to survive. Kerosene will not mix with castor, without ether. Ether provides cooling and easier running. Without ether, you can't use castor and kerosene. methanol and castor mix but that is different again. You could try your biofuel with synthetic oil and preheat the engine some how, but even then the engine won't last very long (if at all). If you mix kerosene with castor, it will separate very quickly and stay separated. There is also the ignition improver that helps the engine from beating itself up.