Hi, I wonder if some one could help ? I have taken off the carb, cleaned and serviced it, set it up as per manual, but I couldn’t get it to run properly, until I undid the brass jet to the right of the carb just under the electronic choke housing, when I unscrew it half a turn the engine runs like a dream, when I close it shut I get nothing ? It was tightly shut prior to me servicing it, and in the manuals it pays no reference to adjusting it ? When I do unscrew it, it runs really well but the screw/jet is loose and subject to rattling around with the engine vibration... should this have a washer on it ? Or rubber 0 ring to keep it in position... any comments would be appreciated.