tinker
Definitions
To attempt to repair, adjust, or improve something in a casual or experimental way.
To work in the manner of a tinker, especially by mending metal household utensils.
A person who travels from place to place mending metal household utensils as a way of making a living.
Examples
He likes to tinker with old clocks in his spare time.
The mechanic spent all afternoon tinkering with the engine to get it running smoothly.
She decided to tinker with the recipe by adding a pinch of cinnamon.