BACK-FIRE

Back″–fire′, v. i. 1. 1. (Engin.) To have or experience a back fire or back fires; — said of an internal-combustion engine.
2. 2. Of a Bunsen or similar air-fed burner, to light so that the flame proceeds from the internal gas jet instead of from the external jet of mixed gas and air. — Back″–fir′ing, n.