If I remember correctly from when I had an empire B, there should be a few tension levels as well as a few speed levels. I'll see if I can track down a pdf of the instructions, but I'd back these settings down all the way. Start at the bottom and take each setting up and test. High settings that still aren't blending is where you want to be.
There you go. Apparently I'm wrong. It must have been the v35 that had the additional settings. Try Strangelove's suggestion. Or maybe try to find a 4 battery pack and use that. The only issue with oiling the belt is that you have to take it apart more than any one wants to take one of those dumb things apart.