Just bled my boiler but it only came on for like a few seconds?

ok, ran out of oil so got some delivered yesterday bled out some oil (half small square pan full-saw some air bubbles coming out of it. Pressed the red reset on to bleed it and then again once I had put the valve back tight, managed to get boiler to run but it ran for like a few seconds and then stopped. Any ideas? Any help would be greatly appreciated and don't say call a boiler company because I can't afford it hence why I bled it myself.