I have a 12 HP briggs and stratton engine that will start when choked and then only run while between choke and full throttle position. I have cleaned carb. And checked fuel supply. Any Suggestions?

It is a fuel delivery problem. You need to make sure pilot jet as well as main nozzle are compltely clear, by choking it you are reducing air delivery to compensate for a reduced flow of fuel through carb. You also stated that you have good fuel flowing to carb, double check and make sure you have no obstructions in tank or fuel filter.

Good luck,
Don

The carb will need to be taken apart and soaked in carb solvent. Install a new carb kit ,adjust to specs and you will enjoy the summer. Rick