so my father ends up buying the 80 cc engine kit from ebay...i put everything togeather and everything worked fine..now it just doesnt start..it has spark and compresion..should i get a racing carb?
of course you should!!!! a racing carb will fix everything and let you blow corvettes and mustangs away every time you touch the throttle...
thats being sarcastic, if you cannot tell.
save your money, try dismantling the carb you have and learning something.
sounds like one of two things happening...
the needle valve in the float bowl has gunk in it, and isnt closing properly.
or, the jets come loose.
there could be other issues, but for now, with what info you have given us, assume its one of those things.
you could just rip the carb off, pour a bit of fuel down the intake, attempt to start it... and if it doesnt start, you know that the carb is fine, its something else being annoying instead. which could be anything from a lousy plug to a popped crank seal...
you have to look at them as three separate systems, and tick each one off the list systematically. starting with the carb/fuelling.