Hi. New to the forum and could really use some help. I have a Genie Z60/34 zoom boom with a Deutz F4L1011F that won't stay running. It will start easily, and continue to run initially for about 20 mins, then shut down. Will restart but not stay running. I did notice that the battery voltage read out shows that it's not charging and when it drops to 10, it shuts down. The battery shows a full charge on a multimeter and the alternator shows 14.3 V output. Suggestions??