I have 1984 and 1991 115 Yamaha's.<br />One is oil injection and other is not.<br />I want to swap lower units but the part numbers<br />are different.<br /><br />The lower unit case numbers are different.<br />61U-45300-13-EK FOR 1984<br />61U-45300-13-EJ FOR 1991<br /><br />Can I swap? What is the difference between "K" & "J"?