Make real sure good is like 1 gl per min or so, and verify the evaporator is clean. I'd open the cabinet or whatever it is in and remove the air filter and run it to be absolutely sure the evaporator has good airflow over it.
If that's not it, I'd suspect the thermostat. Get the schematic and by-pass it. If it's still cutting off, then you do likely have a refrigerant problem and probably time to call an expert as your not likely to be able to unclog an expansion valve or service
the system as I believe most are sealed, look for ports
to hook a set of gauges to.
Very unlikely there is a sight glass on the dryer, but worth looking to see.
As you know, this does sound a lot like not enough water flow through the condenser tube.
Sent from my iPad
using Cruisers Sailing Forum