Mercury 35/40HP 2 Cylinder Outboards Service Manual PN 90-42794--1, Page 19Get this manual
Test Procedures AWARNING
When testing or servicing the outboard ignition system, high voltage is presentBe extremely cautiousDO NOT touch or disconnect any ignition parts while engine is running, or while battery cables are connected on electric start modelsA process of elimination must be used when checking the ignition system without Quicksilver Multi-Meter OVA Tester (91-99750), or voltmeter (capable of measuring 400 volts DC, or higher) and Quicksilver Direct Voltage Adaptor (91-89045), as the switch box and ignition coils cannot be thoroughly checked with conventional test equipmentFollow instructions in the Test Manual included with the Multi-MeterOVA Tester, or Direct Voltage AdaptorAll other components can be tested with an ohmmeterBefore troubleshooting the ignition system, check the following: 1On electric start models, make sure that electric harness and ig nition switch are not the sou rce of the problemCheck that plug-in connectors are fully engaged and that plug terminals are free of corrosion 2Make sure that wire connections are tight and free of corrosion3Check all electrical components, that are grounded directly to the engine, and all ground wires to be sure that they are properly grounded to engine4Check for disconnected wires, and short and open circuitsSTATOR TEST IMPORTANT: Stator assembly MUST BE grounded to engine1Disconnect blackyellow and blackwhite stator leads from switch box2Use an ohmmeter and perform the following testsResistance (Ohms) 120-180 3200-3800 3100-3700 Scale Reading(x 12-18 (R 10) 3.2-3.8 (R 1000) 3.1-3.7 (R 1000)