EFM 350 Fire Problems

I have a question for those with more experience than I do with coal burning. This will be my third winter burning coal and have had few if any problems up to this point. But this week (of course as it gets cold here in the northeast) I notice only half of my bowl was burning. So to me this means maintenance. So I take out the coal so I can get to each individual leave of the bowl and clean it out. Now after having it all back together, the settings on teeth and airflow that I have used for the last two seasons (3-3.5 teeth, 3.5 air) are no longer working. The fire keeps burning out. Right now I have the teeth on max (7 I believe) and the airflow on 5 just to keep up. Any ideas why it changed, And what I need to do to right the ship? Any help is appreciated.
Thanks

Welcome. Please tell us where you are located, perhaps there is someone nearby that can give you a hand with your EFM.

Are you getting your coal from a new supplier or source? What maintenance have you done in the last three years?

Near Albany NY. Every year I would clean out inside with a brush and vacuum out the ashes.
Same supplier, but have had the same load since last year.

Time to check everything over for proper function. Does the auger look intact? Is the fines clean-out plate on the bottom of the pot closed? Do you open the clean-out lever on a regular basis to empty the fines?

Is the aquastat and timer working properly?

Not sure if that 350 has a gear box diff for the auger, but make sure that has oil.

Double check your flue pipes and chimney for blockage.

To answer rob, yes to all. Took me shoveling 2 ton of coal to check end of auger since I have an extension, but yes. Aquastat good, clean out plates are clear, and I regularly use my clean out lever. Just gave a good cleaning and fired it up hoping that it was a fluke. While I was shoveling though I did see a few pieces of chestnut or pea coal. I wonder since I burn rice if a larger piece was near the end of the auger preventing feed.
And Good Prophets, gear is oiled (has a cup or dish under gear for oil that the gear runs through) and chimney and flue are clear.

I meant the sealed gearbox diff that the motor connects to the ratchet gears for the auger.

I read about this oil level and never knew it was in the sealed box.
I had motor problems, to where the motor would trip.
I had to reset it and then after a while it stopped all together.

I hand spun the blower backwards and somehow it helped.

2 months or more later, I just had it "serviced" when I had them come out
to take a look at one of my rads not heating. And they also changed out the autofill valve
The service guy said it was empty or low, so he filled it.

I now know this needs to be checked and fill regularly.

Again, not sure if the 350 has it or not, maybe someone else can help explain it,
Rob R probably can!

EDIT:
I did have half the pot not burning before a few times, not sure what it was cause it would go away.
I know with all the outfires I had when summer started, I was lighting it up sometimes 2-4 times a day!
I would light it up and then hand stoke the hot coals around to the unlit side.
This did seem to help and I then assumed it was from that.
Not unless it was from cleaning out the pot to unstick something one time?

Have you verified that the timer is working? Make it run through a cycle and verify that it sends power to the aquastat.