i recently purchaced a 79 evinrude 15hp off craigslist. It ran great in a tank took it out on the lake and ran great for 20min. pulled out tried again 2 days later. it ran great then died, i check for spark nothing on either plug. I have 0 continuity thru the stop switch when not depressed, and continuity when it is. please help as i feel i may have been ripped off. Is there any way to test the power pack or other tests I can do with out a manual. Thanks for all the help