Nissan Repair: Hello Mr.Von , I have a Suzuki..., suzuki swift, power valve

Question
Hello Mr.Von ,
I have a Suzuki Swift 1994 sedan.
I know you are an expert for Nissan , but if you don't mind answering my question as there is no expert for Suzuki .
The problem is that it consumes much fuel about 200 km for every 20 litres. I replaced the igniton plugs before and also the mechanic has checked my Carburator as it was suspected to be the cause of the problem.
I always see black spots in my shakman which means that fuel is not burned totally.
Also I have black spots on my spark pluggs .
My sparc pluggs are Denso .
Thank you

Answer
The carburetor needs to be gone through as that seems to be the problem.  If you are running rich you will have all the problems you describe.  If it were me I would buy a rebuild kit, a float and a power valve.  That should do it and your mileage should return.