How would you translate this ignition-related phrase?

(2011-01-14 15:20:41) 1. binba Says: There's this phrase in Israel - it borrows directly from automotive repair. "Hatzata Meuheret" means something like "late spark", when the ignition timing is retarded/delayed.
Borrowed, it is used to describe the kind of person who laughs at a joke after everyone else does, or "gets it" last. "He's got a late spark", one would say.

1. What's the proper English term for the mechanical issue?
2. I doubt it's used in the same metaphorical way in English. Any suggestion how you'd mesh the mechanical term with the (Hebrew metaphore) meaning to make a good translation?2. My two cents Says: You actually have a pretty good understanding of the answer to #1 and I can't think of a better way to explain it then you have.

Metaphorically: For the direct english joke term I would use something like." A bit slow on the uptake" or "A bit slow" or in a car sense..."he is not firing on all cylinders" But in my 50 years on earth I can't think of one that would be a direct replacement. Sorry Tag: How would you translate this ignition-related phrase?