anyone else find making google my default search engine harder than the guides suggest?

If you've cleared out the extensions and it still reverts, try Chrome's reset settings option (under Settings, Reset settings). It puts the search engine, startup pages and pinned tabs back to default and switches extensions off without deleting your bookmarks or passwords. Also worth right-clicking the desktop shortcut and checking the target - some adware tacks an address on the end of it.

If it won't stick, something is putting it back - usually an extension with search permissions, or a work laptop with a policy set by IT. check the extensions first, that's nearly always it.