This engine was equipped with a mesh exhaust screen to prevent painful burns. This was the first solution for people complaining about burning their fingers when priming with too much fuel might have caused a small fireball when they applied power to the glow plug.
This is pretty funny! I started my first .049 at the age of 10 and I never experienced this issue. I have never even heard of anyone having this problem.Also, this is the first one of these screens that I have seen. As a kid I am pretty sure that I would have recognized that this screen (like the muffler on my go-kart) was holding the motor back.
I always used a small dental suringe (the kind with the curved plastic pointy tip) to fuel my .049's and also to prime them.