Correct fuel mixture level needle?

Just checked my cylinder head and found to be heavy thick carbon deposits on the top of my pistonhead which it have been cleaned afterwards. I was wondering if it runs on a too rich because the spark plug is black powder on it, so I checked my throttle needle and it seem my dad or someone before him had been moved the level clip.
Which is standard level for this scooter? Move up to one or two or three? or should I start first top and test each level?

sorry my English is not a great!

 

You need to check your main jet as well as needle, needle works across whole throttle range, main jet full throttle, I'd move it up 1 notch and try it. What scooter is it ? ALWAYS CHECK PLUG AFTER EVERY ADJUSTMENT and do one adjustment at a time so you know what has done what !

 

My is Suzuki CS 50 1982

 

Update: adjust spark plug gap it correct gap from Haynes manual book. I smell the fume it quite heavy burn petrol, I will look at the jet tomorrow and move the clip up to one.

 

Auto choke ?

 

Yes auto choke by heating control I have the heating connector paste on it there is nothing wrong with it.

Update: Found faulty with carburettor jet is loose! Tight it up it must have leaked lots of fuel now should have more miles per gallon!