My 064 has lack luster throttle response. Otherwise it runs great. It has the Bing carb on it. I conversed with Woodie and his has instant throttle response with a WY carb. My IPL shows a WJ-65 carb. The Bing on my saw is not compensated but the filter back could be made to accomodate it. What would be the best carb to put on this saw?