I have a eager-1 4.0 HP 20" cut the only number I can find is
143 404322ER0009B I need to replace the plastic gas tank mounted on the top front of the mower.

Willie Jones, June 2005

The best way to find a gas tank for that is to go to the Sears Website. 143.XXXXXXXX denotes it is made by Tecumseh for Sears. The 143.404322 is the number you will need for the search. Go to the Sears Parts store: http://www3.sears.com/ type in your number and search. It comes up...I have tried already.

Scott Deaver B&S Authorized Master Service Technician, June 2005