How does pushing a car that won’t start help start it?

Question

How does pushing a car that won’t start help start it?

In: 1758

Answer 1

The car must be a manual transmission for this to work.

An engine starts by the starter motor forcing the engine to turn until it “catches” and then runs on its own.

When you roll start a car, you build up enough speed that when you put it into gear and then release the clutch, the wheels and transmission now force the engine to turn until it catches and then runs on its own.

Basically instead of the engine moving the wheels, you can use the wheels to move the engine. It’s easier in 2nd or even 3rd gear.