We’ve updated how the fuel meter works in FarmVille 2 – if you find that you’re not able to harvest your fuel pump because the game asks you to ‘Use some first’, this means that you are at maximum fuel capacity.
To check how much fuel you have, you can open your Crop Dryer, and hover your mouse on the orange bar. The number on the right side of the slash (/) indicates your maximum fuel capacity. If you are at or over capacity, you will not be able to harvest your fuel pump. For example, in the image below, the player will not be able to harvest their fuel pump.
Alternately, you can activate your fertilizer plane to check how much fuel you currently have. To do this, hover over watered crops, and click the plane icon in the middle.
This will bring up a fuel counter in the top right corner of your game screen. Again, if you are at or over capacity, which you can check by hovering on the fuel icon, you cannot harvest your fuel pump.
To summarize, you will be able to harvest your fuel pump only if you have not reached your maximum capacity.