I have a NextGen 3.5KW AC genset which I think has the same engine. But the cooling
system is different. Mine has an engine driven raw water pump
but no fresh water pump. Coolant circulation through the heat exchanger
is accomplished by a thermosyphon effect which creates flow due to the temperature and elevation differences.
I looked at the pictures of the Genie and where a belt drive r/w pump is located on mine, there is nothing on the Genie. So it does seem to have a DC raw water
pump which is surprising. It probably uses the same thermosyphon system as mine to avoid having a coolant circulating pump.
It is possible that the DC raw water pump is controlled by the coolant temperature sensor. That too is surprising since another poster noted that you wouldn't get any exhaust cooling
until the sensor starts the raw water pump.
So unless you can confirm the operation of the pump from another owner or the factory, this is what I would do: Put a voltmeter on the DC raw water pump's motor
terminals and start the engine. If you read 12 V and you get no water out of the exhaust then the motor
If you don't read any voltage then you have a quandary. Frankly I can't believe that this unit is designed to delay raw water flow until the engine heats up. That would be a disaster waiting to happen which would melt your water lift muffler
if the controller fails.
So maybe the controller has failed or a relay is stuck or ????
You could just run it for a while and monitor
the exhaust hose and lift muffler
temps with an IR gun. If the lift muffler gets up to 200 deg and still no raw water flow, shut it down as the fiberglass
will soon melt.