Montana confirmed on Monday morning that they have parted company with manager Vivian Emanuel after a string of poor results.
Marc Zeidman and Nick Goodmaker will take charge for the foreseeable future.
Montana chairman Raymond Harrod told JC Sport: "We'd like to thank Viv for all his hard work and effort over the last six months."
Emanuel, who is the first casualty of the JC MSFL season, told JC Sport: "I always knew that rising up the leagues would be a challenge and I have gained some great experience.
"Montana is a great side and I felt that it was time to leave. Things have not gone as planned after such great hope for the season.
"I do want to stay in managment and hope that I can find a new club soon."