Without knowing where your test points are in the system, offhand I'd say you have a possible restriction in the capillary tube, the suction side is bit low for a soda machine/medium temperature application, normally it would run between 18-30 psi on the lowside & 130-180 on the high, depending on ambiant temperature & evaporator temperature, was the machine originally equipped with a R12 compressor? or was it a R134a unit? the reasoning I'm thinking is have you watched the low-side pressure upon startup & does it start in the normal range & then goes low?  ( maybe a bit of ice formation restricting the capillary tube) or a non-functioning condensor-fan? 

I think I have figured out my problem, I was watching the discharge pressure after the condenser and before the dryer and noticed it was functioning from 235 psi to 244 psi and that the capillary tube would vibrate or surge as if it had gas going thru it some times so I figured it had none condensable in it,  Remembering back to when I added the charge after pulling vacuum for 2 hrs I added the 134a without purging out my 4 feet of hose, 2 feet
From can to gauges and 2 feet from gauges to suction line, So I am going to start over, I hooked up the vacuum pump and evacuated the charge after pulling for 1 hr I primed or purged out my hoses by
Hooking up a loose fitting to the check valve in the end of the hose and turned the refrigerant can upside down until liquid came out and then removed the loose fitting trapping refrigerant inside the hoses and then hooked it up to the suction line and then added just the gas let it set and then started it up let it run until I had the right amount of charge
I have now got 165 psi on the discharge 70 F outside temp and 18 psi at suction 44 F inside it looks more right now, It is cooling down quickly I am satisfied it just had air in the system hopefully the dryer is still good and the capillary tube is not surging.