The carb on an Express must be SPOTLESS inside, and properly adjusted. As well the muffler can clog up fairly easily and send your power levels into the toilet.
Oh, and your choke isnt electric. It's mechanical based on engine heat. The old ones love to gum up and stick open or closed, throwing things off. Make sure yours works before you even try to adjust your carburetor.
I wrote a guide on the Express some time ago, and it's written for the older models, but they're similar enough to be some help. Search for garage sale express here to find it.