Small Engines (Lawn Mowers, etc.): Suzuki ac4000gd2e generator, sea foam additive, carberator

Question
Motor runs continuously until choke is pushed back to closed position. I have used numerous times with the choke held open but while replacing plug &fuel filter noticed the spark plug was quite black. I have been told the carberator may need to be rebuilt due to gum up of old fuel? Have run sea foam additive but still requires choke. Please advise?

Answer
A black spark plug indicates the engine is running rich, too much fuel or not enough air.

The engine should run with the choke open, this is how all gas engines should run.  It does sound like something is wrong with the fuel system and the most common problem are dirty carburetors.

I would remove, dis-assemble and clean the carb.  Blow compressed air from an air compressor through all the carb orifices and then spray each hole with carb clean.  Blow air through all the holes again.  Re-install and see if it runs better.

Eric