1994 was the year they transitioned to the new style pump. Both
types of pumps were used in 1994.
if you have the newer Mercury style square pump, the part number is.: 21-857005A1 DIAPHRAGM KIT
If you have the old style 2 stage pump, most parts are available from any Mercury dealer, but it appears they do not sell it as a kit.
crowleymarine.com/mercury-outboard/parts/1469_120.cfm?mdl=EITNAV
Or Sierra brand part number 18-7806-1
BTW, looking at your serial number, your motor should be a 1993.