1985 OMC 65, 100 and 155 HP Models Commercial Service Manual, PN 507450-D, Page 177Get this manual
Power Pack Output 1Set meter switches to negative and 5002Disconnect two-wire connector between power pack and ignition coils3I nsert jumper leads between "A" terminals of connectors
4Connect meter black lead to engine ground5Connect meter red lead to cavity "B Crank engine and observe meter reading6Switch jumper leads from" A" terminals to "B" terminals of connectors7I nsert meter red lead into cavity" A