MSD 8998 Single Channel Digital Ignition Tester Installation - Manual (Page 2)

2 INSTALLATION INSTRUCTIONS
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RPM ADJUSTMENT
The MSD Digital Tester has two rpm adjustments; Coarse and Fine:
Coarse Adjustment: When this knob is turned clockwise the rpm will
increase in 100 rpm increments. This allows a large spread of rpm to
be covered in a short period of time.
Fine Adjustment: When this knob is turned clockwise the rpm will
increase in 1 rpm increments for precise adjustments.
INSTALLATION & USE
1. Be sure the ignition is Off.
2. Remove the coil wire from the distributor cap and install the MSD Load Plug. Connect the Plug to
a ground source. Make sure the ground source is away from fuel lines, the carburetor or throttle
body as a spark will jump the gap.
WARNING: A spark is going to jump across the tester’s gap. Make sure there are no fuel sources
or wiring near the tester. Never touch the test plug with the tester connected.
3. Attach the Tester’s Red wire to a 12 volt source such as the positive battery terminal.
4. Connect the Black wire to ground.
5. Connect the trigger wire to fit your application. This will be the wire with the White alligator clip or
the 2-pin connector for magnetic pickups. Note: The 2-pin mag pickup connector will never be
used with the White trigger wire.
6. Make sure both the coarse and the fine adjustments on the tester are turned to the full counter
clockwise position (zero).
7. Turn the ignition switch On and press the red button of the Tester until your appropriate engine
combination is selected.
8. Increase the Coarse adjustment until you reach the desired rpm. Note that a spark will be firing
across the load plug. The fine adjustment can be used to get the exact rpm you desire.
Figure 2 Adjusting the Tester’s RPM.
Figure 3 Testing an MSD 6 Series Through the White Wire.