I have a Polaris 280 and I just finished installing the tune up kit. After adjusting the wheels per the instructions, I reattached the cleaner to the pool and turned on the booster pump. The 280 didn't move. I picked it up and discovered that if I pull the tension off the idler wheel, the two wheels connected to the drive train start to move. I do not see a way to adjust the tension on the idler wheel, so is there something else I should look at to see why the 280 doesn't generate enough torque to spin the wheels?