I've replaced LOTS of pull ropes over the years, and in fact, I need to replace one on my rototiller right now.
Every one that I've ever done has a chimney-like part sticking up that the pull cord runs into and out of when the cord is pulled/released. That chimney-like part is riveted onto a metal shroud that covers the top of the engine. The metal shroud is bolted to the engine with four small bolts which are on the side of engine, not on the top.
If you remove the four small bolts you can lift the metal shroud off of the engine and then you'll have easy access to the recoil mechanism/pull rope etc.
Maybe yours is different, but I've never seen one that wasn't as I've described.
Tom in TN