Start by looking at your plugs. If they are black, wet, stink of gas - you are getting too much gas. They should look light brown.

And whaddyer mean rough? Does it idle bad? Does it backfire? Is it hard to start? Do you have to pump the gas to get it to start? Does it run ok in the bottom end but back fire or hold back with a load or up a hill?

I have found a lot of running problems to be ignition ones. Best to do the standard plugs and points and set timing, then check the carb.