I have a Craftsman riding mower with a Briggs 283H00 0399 engine. It will not run unless you pour gas into intake. It had a Walbro carb on it and I cleaned and rebuilt it with no success. Fuel bowl is filling. Fuel line flows great. I decided I would put a New carburetor on it. The carb. # was changed to a Nikki carb number. I installed new Nikki Carburetor and it still wont run unless primed thru intake. The bowl solenoid opens and closes with the ignition switch. I have great spark with brand new spark plug. It will stay running as long as I feed it fuel. It was always the float stuck every year I dealt with. I'm at a loss. I'm sure it's something simple. Engine ran great last year.