Refrigerator not working on LP

OK so I have been through tons of threads. I have a 2016 Hood River 178. My refrigerator won't work with LP. it ignites but after flame lights it dies down a little. The model is the Dometic RM 8501. Works great on 120 but won't cool 1 degree on LP. I have taken some of the pieces apart and blown some compressed air on either side of jet and up the chimney(??) a little. That helped at first as it would not even ignite. Now it ignites and stays lit just not strong enough of a flame (I guess) to operate properly. No error comes on just no cooling. I am thinking of trying to pop out the jet, it appears to be lodged in by maybe a little red washer (tiny), and then soak in goo gone but don't want to damage. I have read also about regulators being a potential spot of issue. Lastly, I had an RV guy come look at it and he seemed very uncertain about anything. He called back saying it might be the valve or the burner and he would replace both at $750 for parts and $75/hr. I would have like to see more confidence in identifying the problem before shelling out a grand thoughts. and TIA!