Never put any oil on the internals of an airgun..what you are describing is called Dieseling.. It is basically the ignition of a fuel resulting from the heat generated by the compression of air in a cylinder. When the air within a spring-piston airgun’s receiver tube is compressed, the temperature of the air rises to a very high level, igniting the tiny oil droplets that lubricate the piston seal and walls of the compression chamber. Thus, a combustion and sometimes detonation can occur resulting in production of smoke..dieseling can affect the accuracy and velocity of the pellet..now depending upon the amount of combustible oil that has entered the internal either the air gun will stop dieseling after some time or in the worst case scenario it may damage your air gun internals.
Now, how to get rid of dieseling :
Short answer:
Take it to a knowledgeable gunsmith (which is a rarity in India) He will take care of the gun.
Long answer ....DIY
Take the stock off and clean her up again with de-natured alcohol. Use a blow-dyer on low heat to dry out the gun completely. Allow it to sit in a warm and dry space for 24 hours with the breech open.
Lightly lube the main spring with a low/no solvent carrier moly grease. Use a very light gun oil like Rem Oil to put just a drop on hinges, pins, trigger parts and other mechanical stuff (not near or in the compression chamber or main seal). Re-assemble, use one drop of PURE silcone chamber oil in the chamber (no solvents) and you are good to go.
-Nishith
