on a long pull through the mud or bog the power seems to fade off low or high range. it seems as if it runs out of gas. i have made sure my jets were good and belt is new. the only thing is the guy i bought the quad from had changed the fuel pump and it didnt quite bolt up the same as the original, but is what the dealer gave him. is this my problem, or would exhaust from a 800 be doing this meaning the dual pipes. i live at 4000 feet there is a 152 main and my needle is in the middle, ive also heard that these carbs are know to wear out the needle and nozzle. any one got any ideas?