If all you have done is crack them open (3/4 turn) more like seepage with a few bubbles. If you are not getting anything, try wiggling the injector line a little with the nut loose. I presume you are doing this with the LP only, not trying to start it.
If you do crank the engine over, or have someone do it for you, wear glasses and keep your hands away from the nuts. Serious risk of injection into your skin.