I recently took my dad's 1987 MX LT out of the shed (has been sitting there for 3 years). I cleaned the carbs out but its still dosent run the best. It will bog down in a little bit deeper snow and wont accelerate very quickly(from about 0 to 1/4 throttle), and once I get to a little over 3/4 throttle it starts to slow down again. Anyone know what the problem(s) could be?