Hi ,
I have a Poulan/Weedeater 42 inch Riding mower ,model 450-420. What belt I need to replace tbe deck belt?

Hi,
I will gladly look up the number, link you to a parts manual, etc. if you supply a correct model number. It is usually under the seat, though sometimes on the rear frame and will usually begin with one to three letters of the alphabet. I have not seen one with a hyphen, either. It can sometimes matter whether it is gear driven or hydro. The year is usually critical because of design changes.
Peace,
Clarke