Torque specs

[Bustd knuckles]

Hi guys,I'm new and have a question. I have a KubotaZD21 and it's a 3cylinder diesel. It was running rough and after changing fuel filters and cleaning the air filter it was determined that I had 1 or more bad injectors. The owners manual wasn't very helpful but got them out and sent to be rebuilt. As it turned out we had 2 injectors that weren't right so all is good except for one thing. What is the torque specs for the fuel injectors as they are threaded into the head and were pretty tight coming off. So, any help would be much appreciated-