Hey thanks for the info. It's not that screws are too expensive for me, it's just that i hate having to pay like $10 to ship a couple of screws. As for the heat sink thing, every time i pull on the pull-start cord it seems to be leaking air/oil at the contact point. I can't take off the heat sink right now because 2 of the screws are stripped but i'll have them taken out with a help from a friend soon.
Edit: Oh and those screws i need are actually Round Head M2x6mm and M2x18mm screws... which seem to be impossible to find. There doesn't seem to be any designation of the pitch with the "M2x6mm" notation.