Thanks to all for your suggestions. I drilled some holes in the thermostat and upgraded the cap from 4# to 7# as a start, and it seems to have cured the problem. One other question. The temperature gage when cold, sits at 220 degrees, and previously with a 195 degree thermostat, it would go down to 180 degrees on the gage when warmed up. Now I have put in a 180 degree thermo, and it goes down to 195 degrees when warmed up. Shouldn't the gage rest at the low end of the scale, and go up from there. How to correct?
