Hi guys. Picked up a little MTD saw from the tip for free. Replaced the primer bulb and fuel lines, which fell apart in my hands, and it is now a runner but bogs down on full throttle. It will take full throttle with half choke on but adjusting the H fuel mix doesn't appear to make any difference. Would an air leak at the carby gasket be the most likely problem?, or should I look for something else?