The screen is definitely not original equipment. Some aftermarket places like J.C. Whitney sold similar items as "gas savers" intended to break up the gas/air mixture into finer particles and supposedly improve gas mileage. This one looks like a homemade copy of one of those things. I call those kind of gimmicks P.T. Barnum Specials ("There's a sucker born every minute!")
The accelerator pump only has one outlet, so a single stream is OK. If it's stumbling on acceleration, you might have a vacuum leak somewhere, or the ignition timing might be a few degrees late. Try loosening the clamp around the distributor housing and turning it just a little counterclockwise - - - -don't overdo it, a little adjustment goes a long way.
Jerry
