I wonder if the essentric is bolted in correctly or tight enough. I've never had any issues in this reguard and have had pumps on and off several times. The only thing I can think is that the essentric has a little tab that has to be in it's hole, this is what keeps it in it's off centered position. Almost sounds to me that the essentric is just spinning in a circle versus oblong pattern. I would say turn the motor over by hand and put your finger in the fuel pump hole and feel if the essentric is acting as it should...