when you say "richen him",what needle do i have to turn?
the high speed needle ore the low speed needle.

what i know is that there is a needle for the mixture that the pipe from the fuel tank is connected to, this is the needle for the "rich" control.
additional i have two screws near the carburetor.

when you are saying "high speed needle" and "low speed needle"
which is which on my engine?

Thanks.