try inputting ctcss 141.3 on all your repeater channels and keying up and throwing out your call sign. If you hear it ID immediately or you hear a squelch tail after you key down you found a repeater. 141.3 is considered the travel tone and many open repeaters use it. After you find a repeater try calling out at different times of the day on it requesting permission to use it. That is what I do to access unlisted repeaters. So far everyone I have contacted has been very nice and usually don't mind you using them as long as you are licensed and don't abuse it. Things most repeater owner don't like is kerchunking, foul language, interruptions of on going conversations, and unlicensed users. Most repeater owners welcome more users so don't be mic shy.