Good morning, and welcome back. I do not know any "coal guys" in your area, but if you are reasonably handy, you can service the unit yourself. Start by reading this thread, it is an excellent overview of the different components and how the fire should behave.Keystoker Ka-6 operation guide.
Generally, a cleaning/service includes brushing out the interior of the boiler, cleaning the smoke pipe, and vacuuming fines out from beneath the grates. You might have to adjust the stoker to produce more heat, but the unit needs to be cleaned first.