Isn’t that an Austin engine on the book cover? In which case, you can’t unfuck it. 
While we’re on the subject, the second world war American war correspondent, Ernie Pyle wrote:
Once, on a misty Scottish airfield, an airman was changing the magneto on the engine of a Wellington bomber. Suddenly his wrench slipped and he flung it on the grass and snarled, “Fuck! The fucking fucker’s fucked.” The bystanders were all quite well aware that he had stripped a bolt and skinned his knuckles.