So, my question is, how do I tune this one? are these red and white bits shown in the photo anything to do with it and what do they do?
Thanks in advance.
Surprise no one has answered this easily one.
First those are the limiter caps on the fuel mixtures.
As with any new find find or repair of a two cycle that doesn't run well as you describe is to ultrasonic clean the carburetor and install a new rebuild kit. Those fuel mixture screws do need to remove to clean the carburetor properly. Look at the retainer clip and you will find a split that you can put a flat screwdriver into so you can open it up so the limiter caps can be removed and the screws.
After cleaning re install the screws lightly seat them and then back them out 1-1/2 turns each. Then start the trimmer and adjust the L speed first for best idle speed followed by the H speed for best top speed with a slight 4 cycling.
Once you are satisfied with the adjustments then reinstall the limiter caps in their mid range positions.