Firstly, the tickover speed is controlled by the big white knob under the carb.
Secondly, with the engine thoroughly warmed up, & the choke off, the engine in neutral, screw the big white knob in until the engine is running smoothly (it will sound approximately 1½ times as fast as your car sounds at tickover) What you don't want is to hear each "thump" of the engine. The 1300 RPM is really just a starting point to get the tickover as you want it. I don't think any of us here have got it set exactly to the book, & it's certanly not something you need to pay a mechanic to do for you. One of the reasons being that you'll probably have to give it a tweak now and again to get it set as YOU want it. Again, it's just one of the things you'll learn with experience. :2tup:
Edit :- I used the word "tickover". I think the American word is "idle speed"
