Hello, I recently bought a Case 450 series 3 skid steer with 2300 hours. The machine starts right up with no hesitation in cold or warm weather but, smokes during and after warm up when throttle is anywhere between idle and full throttle. it does not smoke at idle or full throttle. Engine purs fine at idle and full throttle but will spit and spudder a bit with throttle positioned anywhere else, along with smoke. Smoke is blueish in color but smells rich like fuel and not line oil. I changed all fluids/filters and now im looking for the next few steps I should take to diagnose the problem. Machine is clean, unabused, and there is no sign of oil leaks or wear anywhere. Any ideas on what my problem is and where I should start? Thanks-chris