Lost a part

It is there to hold the needle from sliding up when the throttle slide moves down. Any washer that fits the slide can easily be used to replace the one you lost. The slot is for the cable to move in. Any washer can be used if you simply cut a small hole or slot for the cable.
Keep in mind the needle clip needs to be held down solidly so be sure the hole in your replacement washer is smaller than the needle clip.

the hole in the washer is the critical part, if the hole in what you use is to big then the C-clip that is on the needle will slide through the hole in the washer and allow the needle to rise out of place, anything that is large enough around for the spring to press against and has a hole/slot small enough that the C-Clip cant get through it will work, if you have some tin snips you could make one out of a piece of a tin can lid or any other similar thickness flat steel.

Map

I lost one myself a while back (it's probably deep in the 'stuff' under my workbench).. I just used a dremel cutting wheel to make a new one out of a small washer. Hold it firmly, or you'll be making another before you're done the first replacement.