My Malta 3hp starts fine but once i put her into gear and try to turn up the reves she dies. it also looks like the spark plug (which works fine) is getting wet so i suspect the fule mixture is too rich. the carbureter only appears to have one ajustment screw (apart from min revs) which dose'nt seem to do anything.
Any ideas as to what might be wrong?

Also dose anyone know where i can get an exploded diagram of a Malta 3hp carbureter or a parts listing as i fear that the previous owner might have lost a part from it. but im not sure if he did or if the part is not supposed to be present.
any idias greatly apreciated.