Route 6 Equipment Parts, Inc. GET THE RIGHT PARTS THE FIRST TIME!! Detroit Diesel 3-53 Series Constant Speed Governor and Fuel Pump. # Marked – 23509513. Terms & Conditions of Sale. All parts guaranteed to be in useable condition unless otherwise noted. NO EXCEPTIONS WITHOUT VALID PROOF OF EXEMPTION. Route 6 Equipment Parts will not be responsible for any issues resulting from failure to confirm fit or finish before ordering.