The 2100s is the proper carb for the 235.
As Wrenchbender said, you may have an incorrect float level, or incorrect main metering jet.
Loss of power is also a symptom of using E-10 ethanol (regardless of what our government would have you believe).
Check the specs on both the metering rod and main metering jet. Pay no attention to the numbers (people drill out jets, and emery metering rods). Use a micrometer and get the actual specs.
At the same time, check the float setting.
And, check with the manager of your local station to see if you are burning ethanol. There are calibration changes you can make.
Jon.
