I am trying to fix a friends Craftsman snow blower, it is powered by a 8HP Briggs overhead valve engine, the stamped production is 010804, so it is a 2004 as I understand. It has a one speed carb, no throttle control, no points. Just a coil triggered by the flywheel. The machine runs good when it runs, but to start it, I have to hold the throttle closed with my hand while pulling the cord, and even then it only will start sometimes if I warm it up (bring it inside). The spark is pink and erratic not bright blue like I would like. I have cleaned the carb, it is getting fuel and has good compression, I think the coil is failing. Do these coils go bad? I am not use to replacing coils but I have been out of the repair business. Any help would be greatly appreciated!