Mercury Mariner V-250 V-275 Outboard Service Shop Manual 1990, Page 36Get this manual
SWITCH BOX(ES) REMOVAL AND INSTALLATION
Switch Box Removal
1Disconnect wi res from switch box
2Remove screws and lift switch box from engineSwitch Box Installation
1Insta ll swi tch box to engi ne wit screwsMake su re that switch box is grounded to engine thru mounting screws, and ground lead
2Reconnect wires to proper terminals of switch boxSecure ground lead to switch box using screw Wires with yellow identification sleeve must be connected to lowe switch boxLower switch box fires cylinders No2, and 6