With R-414 you don't have to change the cap tube, or oil, just the filter, and start off at 80% and adjust from there. The pot will be on the upper board, if there is one, depending on the age of the machine. The overrun is the amount of air whipped into the mix and is controlled by the tube that is inserted into the hopper drain, small hole in that tube goes down. Usually the temperature of the product in the barrel is controlled by the setting of the constant pressure valve. I hope this helps, soft serv machines can be a pain. The machine you are working on may use a barrel temp control, or a solid state temp control and a temp probe. If you want a real challenge, try a Mickey D's soft serv machine.