Carburetor choice

There's still quite a few cheap alternatives to getting the stumble out of the carburetor you have. I think maybe mentioned was the accelerator pump. There's different springs for them and different adjustments on the arm. Just adjusting the arm is extremely simple and right out front. Maybe trying some different step Springs or even metering rods. Also you can put larger or smaller squirters for more of a squirt at tip in to get the bog out or stumble..
What do your plugs look like? If you want to buy something maybe an a/f gage they're not that expensive and pretty easy to hook up..