What is the proper way of using this tool on a VX225TLRY (225 Vmax)? The part number I have is 13-YB-06795. I tried it last weekend and followed the service manual, however the manual does not say what to do with the other connection on the tester. The engine ran like it was on half the cylinders and the test bulb did not flash at all. I ran the test after the engine had been runing for at least 30 minutes. I did not run the test for more than a few minutes because the engine ran poorly with the diagnostic indicator connected. Any instructions out there on how to use this thing?