The engine continually changes RPM, it is as if I were gunning the motor. It goes from a slow idle up to a fast rev and back down. Any ideas?
Bad fuel, namely drops of water passing through the carb.
Turned out it was a plugged gas cap. With the cap off the engine ran fine. It must allow air into the tank somehow.
I cleaned out the cap real well and now it seems to work without the engine hunting, revving up and down. Hope this helps someone else as well.