Why does the word 'coax' in "the engineer could only coax the engine into a spluttering life" suggest that the engineer put in great efforts?

Answer 1

The word coax means "obtain something from by gentle and persistent persuasion."

You could infer that if it was necessary to coax the engine to life, than the engineer must have spent time and effort to get it started. Otherwise, the author would likely have chosen a different word.