1978 Ski-Doo Shop Manual, Page 312Get this manual
SECTION 05 SUB-SECTION 03, (MERC-O-TRONIC TEST) (
ADJUSTMENT OF SCALE NO.3 FOR TEST NO.910
1Turn selector switch to position no2DISTRIBUTOR RESISTANCE2Temporarily attach small black and red test leads together3Turn adjustment knob for scale no2 until meter pointer lines up with left side edge of OK block on scale no24Unclip test leads and proceed with test no9
TEST NO.9 TESTING FOR HIGH RESISTANCE IN PRIMARY CIRCUIT
1Turn selector switch to position no2DISTRIBUTOR RESISTANCE2Connect the red test lead to breaker points terminal3Connect the black test lead to armature plate4The meter pointer must return within the OK blockIf the meter pointer is in the high resistance band, this indicates that there is foreign matter between the breaker points