Tom, welcome to RcK

You only need to block the exhaust before starting, and only if fuel isn't getting to the carb.
To stop the engine either grab a rag and block the exhaust or pinch the fuel line to the carb, just be careful as this will cause a sudden rush of power where it leans out the engine before cutting it out.
Engine RPM can be adjusted by the small screw with a spring behind it under or around the base of the air filter where it's cable tied to the carb neck.
As for the manual, try emailing
nitrotek.co.uk and see if they have one spare... they also do replacement parts for the nb16t.
Hope that helps

Stu
