The new motor fits into the old mount. Uses the old linkage arms. They should have not been disturbed and no geometry changed. However, there is and adjustment for the motor. As Mike says, check the free movement of all that and be sure motor is still tight at it's mounts. If worst comes to worse, the motor disconnects from the linkage quite easily with a spring loaded clip. This clip can be removed and the linkage set aside up in there to see if the motor runs good while disconnected from the linkage(s). We are not sure yet if you have a mechanical or and electrical problem. We will find it with your help. I don't want to give you any electrical tests until the mechanical is double checked.
With you in a learning curve, you need to know how the wiper motor installs in order to see if it is correct or has become out of whack or to spot anything wrong with the operation. So look at this video to get some idea. It is a very grainy video but may help.
Click Hereis another to help understand the first video.
Typically the wiper motor is installed with it's own inline fuse from the ignition switch "ON" or "ACC"
