howzit Yuvan
i had a similar problem. but my question is why dont you check why your plugs are filling up with oil first, and then i would suggest checking your starter, because if its swinging but nothing is happening could mean no spark which would usually mean oil on sparkplug,to be honest i wouldnt just go and spend money,i went through spending money on everything that people suggested,but i kept on taking everything back, also maybe you must check the sensor on the head.
let us know whats the problem please, hope you come right