I changed the jackshaft on my sled and tried to start it but it won't fire. The last time it ran was when the shaft wore off and it was running fine at that time. I pulled the plugs and checked for spark, tried new plugs, unplugged the kill switch, made sure ground was good & hooked and unhooked the ignition switch (when I got it the ignition was unhooked and it worked) all without getting any spark. I don't have any guages or meters to check for spark (not familiar how either) so wondering if there is something else I can check? Any help would be appreciated.