The parts list and manual area is for people that support the board with a donation.
As to the third hose that is for the decompressor and if that has not been connected for some years the bet is that you have had dust go into the cylinder and the rings are worn.
The valve in the carby should be set on "C" if it is a white valve.
Regards,
Bruce
Please do not PM me asking for support. Post on the forums as it helps all members not just the individual.