Re: Universal 5411 Cooling
The operation you describe initially is how it should operate - a little water out the exhaust until the thermostat begins to open, then increased flow. However, the flow should go up and down with the power as the need for cooling changes. Sounds like its not closing down again after you reduce power.
A new thermostat is worth a try. You're going to be shocked at what they cost however, but its worth having a spare onboard.