Briggs and Stratton Surging Issue

I have a Briggs and Stratton model 219802 that I had some issues with so I took it apart, cleaned and rebuilt the carb, emptied the gas, and changed the oil. I put it back together tonight and got it started fine but now it is surging. I can hold the governor steady with my finger and it doesn't really fight me and the surging goes away but when I let go it comes back. I took off the governor linkage and tightened the spring but the problem is still there. What could be the issue? Thanks for the help!

Most surging problems are caused by a lean running condition. I would be checking for leaks between carb and block, low float level, clogged idle jets, poor fuel flow.