Kohler generator runs but no water flow. No suction or lost prime

I take it that this unit runs the power on board and is permanently fixed in the boat
you mention new impeller so logically that means that it is water cooled drawing the cooling water from outside (underneath the boat)
pursuing logic further if that is the case then there is a shut down circuit for the water flow to prevent overheating should the water inlet become blocked ( weeds, plastic cloth etc)
from your question and statement I would be looking in that area to make sure water flow is not restricted or the protection circuit is operational ( no corrosion in terminals and wires )

Is the board getting power, is the control lighting up?
Do you see any error codes on the top side control?
Improper flow will give you an error code, caused by flow issues or a faulty flow switch. Make sure all gate valves are open and the water can flow freely.
If not then check your Hi Limit sensor. This is the overheat safety sensor if it fails the tub will not function at all.

It sound slike water impeller is not giving enough flow to the heat exchanger

I have a kohler marine generator that shuts down when it reaches operating temp of 200/210 degrees. It runs for about 5 minutes. Already replaced impella and have sea water pumping through, coolant level is good. Any suggestions? Thanks

NOT THE MOTOR ,THE SEAL... JET PUMPS ARE NOT FOR POOLS.. LOW FLOW HIGH PRESSURE.. YOU NEED HIGH FLOW LOW PRESSURE ... IF NOT YOU MAY HAVE A SUCTION LEAK OR A BAD SHAFT SEAL... VOTE JAY

I don't know what is your system set up. However, the system set up should be the following;
1. Your 1-1/2HP sprinkler pump must be installed at
a fix location nearest the water source. (Complete
with power and plumbing lines.)
2. At the end of the suction line is a vertical check
valve with strainer.
3. The suction pipeline must be connected to the
suction port of the pump.
4. At the discharge port, a flow control valve tee must
be installed. The flow control valve tee top is
covered with a plug, which serves as the priming
port when opened.
5. After the flow control valve, connect a short nipple
so that you can put a gate valve to stop the water
flow or allow the water to flow. You may connect
a pressure tank at this point or you may connect
the pressure hose going to the sprinkler.
6. To prime the pump, open the plug at the flow
control top. Fill it full with water, replace the
priming port plug.
7. Turn the flow control valve to full closed position.
8. From full close position, switch the power on.
9. The pump now run on and off due the pressure
switch setting. Slowly open the flow control valve
such that the water pressure remains steady.
10. Take note of the pressure.
11. Shut the power off, and connect the sprinkler
pump hose.
12. Put the power back on, and allow the pump to
run with the sprinkler.

Under this set up, you can run the sprinklers when your pump is running. Hope this will solve problem.

Does the kohler generator have shut down sensors for low oil, exhaust temp and such? If so, check the sensors.


I checked the kohler website and noticed that one of the option was the siphon break. Does your genset has this? I had a similar problem like yours and my siphon break was blown. It was replaced.

What is more, do check the exhaust system of the generator and see if there is water flow.

Yes, it can be fixed.Assuming that your water system is pressurized, take the following steps;
1. Shut the power off the lines going to the pump
motor.
2. Drain all the water inside the pressure tank by
opening the drain plug. After emptying the tank,
replace the drain plug.
3. Unscrew the priming port plug and fill it full with
water. And at the same time fully close the
flow control valve.
4. Put the power back on, and slowly open the
flow control valve until the water flow stabilize at
20 or 30 psi at the pressure gage. This could be
at 1/4 open or 1/3 open, depending on the water
supply at the suction point.
5. Check and set the pressure switch to be off
at 40 psi.
This will solve your problem.

You have a defective pressure switch.But replacing the switch. Do the following; Open the pressure switch cover, and find the two adjusting nuts. One is for the cut-off pressure (40psi) and the other is for the cut-in pressure (20 psi). Adjust the the nut with a longer stem counter clockwise (loose) with the pump running. Take care not to touch the power line attach
to it. Continue the adjustment until the pump stops,
at 40 psi. Then, observe - Pump must stop once the
pressure is attained. Then, open the valve until it
start (20psi).. Then you can adjust the other nut to
cut in at 20 psi.
To prime the pump; open and fill the priming port full
with water.and replace the priming port plug. Set
the water flow control valve at full close position.
Switch the power on to run the pump and slowly
open the control valve to appropriate setting such
that the pump doesn't lost the suction. Send your e-
mail for further comment. God bless u

1. Suction strainer with checkvalve must be always
under water.
2. Check the suction checkvalve if holds water. Water
must remain steady when primed.
3. Open the priming port, and fill it full with water.
4. Close the flow control valve.
5. Switch the power on and start the pump.
6. Then, slowly open the flow control valve, to the
level such that it will not break suction, and
stabilized the water flow..