did you say you replaced filters? if not replace the one in the carb and the other (if you have one)
1st thing is to change the filter for the carb as Irish said. The way dirty paper filters work is fuel will go through them, as the fuel is flowing they start plugging up and slow the fuel down. When you take the pressure off the filter, the contaminates loosen back up until you start up again with pressure, then they start the plugging process all over again until the filter is so dirty it will not allow fuel or very little fuel to go by.
If that does not solve the problem, you might have gotten enough stuff that bypassed the filter and got into the carb. that the carb may need to be cleaned.