Briggs and Stratton 126T02-0301-B1 motor won't idle but runs at full throttle.

Hi everyone new guy here and could really use some help. I got this power washer from my father who used it twice and put it away. It has a briggs and stratton 126T02-0301-B1 motor on it. So far I have tried changing the oil, cleaning the carb, when cleaning did not work I replaced the entire carb with an oem replacement, and when that didn't work I changed the spark plug. The washer fires right up on the first pull as long as I have the trigger pressed on the sprayer. It will run full throttle this way for as long as I keep the trigger down. Once I let go it dies. I have checked that the auto choke arm is in the right position and it does seem to be. I really would love to get this thing working but I am completely out of ideas on what to try. Any help would be appreciated!

Briggs and Stratton 126T02-0301-B1 motor won't idle but runs at full throttle.