Problems letting out choke

I have a 88 b2200. First off the electric choke has been replaced with a manual why idk. The engine runs awesome when the motor is choked but when i open it it will just die. I have let it warm up for about 20 min or so and same result. How ever if i give it gas once i open the choke the engine will stay running, once i let off the gas it will die any ideas.

Sure sounds like it's running lean when the choke is open, so it needs additional gas to compensate.

What happens if you don't open the choke all the way?

well that's the thing the choke that was put on in place of the stock electric one had been set up so its all the way or not. what would be the proper way to adjust the air fuel mixture screw.