What is your fuel pump pressure at the carburetor?
The 216 should be 2-4 psi. I'm not sure what the specs are for the 261 but it's probably no more than 6 psi
Too high fuel pressure can cause the fuel bowl to overflow and flood the engine at all speeds.
Good question, I'm using a small electric pump but sadly is has no numbers on it... I doubt the pressure is too high though as you can hear it starting to struggle once the carb fills upp, and I haven't really seen any signs of flooding either.
