If it's running lengthwise, I doubt it'll be any problem. I'd get some liquid super glue - not the gel - and flow some into the crack to seal it up.

Then, string it up and check the tiller to make sure the cracked limb isn't way weaker than the good one. If it passes that test then you can go on to drawing a few times.

Do the 1/4, 1/2, 3/4 and full draw routine a few times to work the limbs. Be extra careful to listen for cracking sounds. If it passes that test, then you can go on and shoot it, still being careful to listen and watch for any signs of breakage.

If it holds up for a couple dozen shots, the bow will probably be fine.

Wish I could find a bow at a garage sale. Everybody else keeps stumbling across them instead of ME! [&o] IT'S MY TURN, DANGIT!![&:]