I did a carb rebuild ,tune up and impeller on a Johnson JW 3 HP 1960 motor, the screen was missing. I ran the motor without the screen and it preformed nicely, I had a screen in my collection of parts so decided to try it, I noticed that the motor idled down a little better and the throttle response was a little crisper and smoother as you throttled up. It wasn’t a huge difference but noticeable to me. Those little screens are not cheap, I have seen them for $25 on Evil Bay.
