If you already haven't solved the problem by now, the meter was wired up reverse polarity. Just reverse the two wires on the meter & it will atart running in the right direction.
Cannot be hour meter wired up wrong. Wires to hour meter have never been off, the meter worked correctly for the first 100+ hours. The only thing that has been changed is the battery. The battery is wired correctly...Red positive, Black negative. Also, does the hour meter reset to zero when the oil and filter is changed or is it susposed to keep going to indicate the entire number of hours the engine has been run during its life?