Hey, a friend brought up an old 70 somthing Jag, single carb, dual cylinder, premix, sled and we can't get the thing started. We drained the gas and put in fresh stuff (properly mixed), changed the plugs, and pulled a thousand times. The head light comes on, but it seems like its getting no spark. Like a kill switch is stuck on kill. What should be my first steps twords getting this started. How can I test the spark? This thing ran eariler this year, but at high speeds would bogg out and loose all power, if you waited a second and slowly accelerated you could get up to speed for awhile. At the same time that it ran it was still really hard to start. Maybe the carbs need cleaning? Thanks for all your help in advance.