Can't get combustion right

I finally got my Triangle Tube Prestege Solo 60 back together everything seemed OK. I had to replace the venturi and some gaskets along with the igniter and wire. I used a UEI C161 combustion analyzer to check everything. the specs are O2 below 4.7 and the CO2 above 10.7 with the throttle screw backed as far as it will go I can only get 6.2 O2 and 9.0 CO2 I'm using propane and my gas pressure is at 12" WC. Any ideas, tried calling TT Tech support, after I finally got thru was cut off, called right back and was #12 so left a message , no reply yet