have a 2000 2510 4x4 that I've acquired and been resurrecting. Cleaned fuel tank and carb., new brakes, cables, water pump, etc,etc. Have bad engine hesitation, stumbling on acceleration. Just lays out flat on its face. Compression 180/170. Adjusted valve clearance. Only minor adjustment, but no change in performance. Ran some Sea foam through carb. intake..helped slightly. Plugs are black with carbon. Ran pilot screw in and out but didn't help the stumbling problem. If I feather the manual choke, can get it to respond. This thing has good power if you can feather it past the stumbling. Any thoughts.??