There has to be something wrong with your airflow like maybe the fan drive belt is slipping. Sometimes it is necessary to attach the belt idler spring to the bottom of the separator frame or drill another hole in the frame to give more tension. You should also check the air splitter and set according to the book. Another thing to look for is anything that might be blocking airflow. If your aftermarket spreader is causing trouble I would lean toward simply removing it. Tom in MN