http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1QB0O2WTZ1QB0O3BL7&year=1984&make=MB&model=300-SD-002&category=D&part=Primer+Pump+Assembly
http://www.***************/search/productx.aspx?sid=lphrhrybiw22pj55ow2ewm55&makeid=800016@Mercedes&modelid=1194038@300SD&year=1984&cid=22@Fuel%20%26%20Air%20System&gid=6259@Diesel%20Primer%20Pump
As you will soon find out,$9.25 is certainly much less than what any shop will charge you to bench check the IP!

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )