Replace it with another.
Never use Motor oil on a BB gun. It will eventually ruin the seals and O-Rings.
Gregory O. Smith has written: 'Is the oil running out?' -- subject(s): Petroleum industry and trade, Petroleum reserves
Two and an o-ring are supplied in the oil filter replacement kit..
Your motor could be siezed. I would purchase a replacement motor. A.O. Smith motor replacements are affordable and then you will be covered by the manufacturer warranty. You can find the lowest prices on A.O. Smith motors (and Emerson motors) with free shipping at www.swimmingpoolsetc.com along with any other parts you may need for your pool.
A little lubrication (motor oil) on the o-rings will make assembly much easier.
A. O. Smith was created in 1874.
Robert O. Smith was born in 1942.
Robert O. Smith died in 2010.
G. O. Smith was born in 1872.
G. O. Smith died in 1943.
Edwin O. Smith was born in 1871.
Alexander O. Smith was born in 1973.