Blodgett Oven Vents?

Does anyone know how to adjust the vents on a Blodgett (999) Deck Oven? I can’t seem to get the temp right on my oven, I keep burning the bottoms of the pizzas. Seems the stones get too hot. I did a search and found that it might be my vents, not sure if this right or not. I have a double stack with the top one working great and has for 3 years now, but my bottom oven has been a fight to get it right. I at first thought it was a bad thermostat, but a new one has not changed the baking problem. Any advice with on this would be great, I pulling out what hair I have left out over this…

Thanks in advance,