just bought a 61 merc 60 kiekhaefer 6hp. i have spark with a spark tester but no spark with the plugs that came in it. they are autolite 303's. tried plugs from advanced auto parts champion 841. still had no spark. points look good and wiring looks good. have dvom hooked up, one end in plug boot and while holding the other to ground i did get shocked... not sure whats going on... plz help.