Dirty propane ?

Hello all...

I have a 4million BTU propane pool boiler. It's a Pentair "Mega Therm"... Laars makes it....
It suites up in 48 hours of usage.... one issue is keeping the water at 110degrees or better but the flame is quite yellow.... it's an atmospheric boiler so I don't have much in the way of adjustments other than air shutters..... manifold pressures are within specs... what have I missed or what can I do to get this boiler to run more clean?
Jets are a 38 for 7,000' ASL..... and installed by the manufacturer...

Any help is appreciated..

:-)) KCA