First off all, hesitation upon acceleration is frequently an *ignition* problem, not a fuel problem. You should double-check that your distributor cap, rotor, spark plugs, plug wires, etc. are all in good condition. Also make sure that the mechanical and vacuum advance mechanisms on the distributor are working properly. One final ignition item is the vacuum source(s) to the distributor vacuum advance. These may be run through a temperature-controlled vacuum switch. If that switch is disconnected or has failed, that could cause the timing to be incorrect once the engine warms up. If all that checks out, the next culprit to check is the accelerator pump circuit(s) of the carburetor. The accel. pump is a device that squirts liquid fuel into the carb. throat as you quickly open the throttle. Check that the accel. pump is properly adjusted and that a good dose of fuel is squirted as you work the throttle linkage. Apparently, sometimes adjusting the idle circuit to the "best" setting can cause acceleration bog as well (see link below) That's something to look into if all else fails. http://www.thecarburetorshop.com/Troubleshooting.htm Good luck.