Older fridge cooling Better on 110 than propane

Okay so I tested my pressures. 11' with no draw from appliances. With the generator on it was 10". With the furnace on also it dropped to 9". With the refer on also there was no noticeable drop. I also tested the draw across the gas solenoid and it was 108.5 ohms. What say any of you guys in the know? Is there a problem? Also there is about a 1/2" clearance between the condensor and the wall. I know, it's excessive and I will take care of that but, again the unit works fine on ac and 12v.