I recently purchased a 1993 Yamaha Big Bear 350 for $300 from a guy at work who could not get it running, getting rid of old fuel and changing the plug it fired up, it has a new carb rebuild that was done before i bought it, problem i have is that it only starts and runs on half choke, even in the -15 celcius canadian weather today. im not sure where to start on this, any help would be great, thanks.