Kohler Power Systems 15KW has me stumped

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RonR

Guru
Joined
May 22, 2019
Messages
713
Location
USA
Vessel Name
Triton
Vessel Make
48' Golden Egg Harbor
2015 Kohler 15KW Gen Set. 30 hours on the clock.
The PO had this unit installed new, and for the first year it ran great, then he had it serviced by Kohler and it then started this problem 2-3 months later. He always thought it was the undersized sea strainer and feed line as it was 3/4. (has 1.5 sea cock)
It will run for about 1-1.5 hours and then the high temp alarm comes on, and it shuts down.
Since our ownership I have replaced the sea strainer to a 1.5, upsized the feed hose to 1.5. Replaced the impeller, and thermostat. Changed Oil/filter/air cleaner/Zink.
When I check the thermostat housing with a temp gun it reads 170, the heat exchanger reads 160, the exhaust mixer reads 145. The factory thermostat is a 190, and its the only one offered (took 2 months to get). The high temp reading on the panel says engine temps are 170. Good water flow out of the exhaust, and its not all that hot, hard to get an accurate temp.

While I was waiting for a new thermostat to show up I ran it without one at all. It never shut down, but it did start smoking (unburnt fuel) as I don't think it was getting hot enough for it work right. Once I put the new thermostat in it stopped smoking once it got up to 170, and then shut down to overheating.

I tried disconnecting the temp sending unit (factory one is 3 months out). But it reads a ground fault and will not start. I have pulled the temp sending unit out and blocked it with a plug. But it will only run in forced mode as it reads no temperature.

This is what I am left with.

1. The temp sending unit may be faulty?
2. The Kohler service guy may have done some kind of reset on the computer for the wrong model? And I need to call them out to reset it again as I do not have the fancy cord, or the program on a lap top to read it.

Thoughts?
 
Last edited:
My 1st thought is the sender or switch. Does it have both? Or one or the other. For a 2015, I'd expect a sender.

Look at the resistance table for it. Find a resistance corresponding to operating temperature. Disconnect the wire from the sender and ground it via the resistor. The generator should run. Let it get up to operating temperature (monitor with a gun fir engine safety), then measure resistance between the sender and a good ground.

If the engine wouldn't run with the resistor, double check the table, but that might point to a problem with the wiring or controller board.

If it ran with the resistor, that points to a problem withbthe sender. That can be verified by showing that the sender is showing the wrong resistance for what you are reading on your gun, and, specifically resistance for a higher temperature.

These values are normally in the service manual. But, if you look at the sender, you may find the manufacturer's number on it. Kohler likely doesnt make it. From there, you may be able to get the part faster and also look up the resistance table.

If you know someone else with the same generator, you can also check resistance on theirs before cold start and immediately after warmed up shutdown.

What model genset is it?
 
Thoughts?

My honest thoughts on Kohler gensets are rather rude. Modern Kohler genset design seems to follow the kool aid of "auto-everything", implying that owners are idiots, and only Kohler knows best on how to start, monitor, and stop their gensets via microprocessor control, esoteric error codes behind hidden menus on LCD screens, and compounded by incorrect and misleading maintenance information. Making troubleshooting almost impossible for the average boat owner.

Having gotten that rant off my chest, I suggest you save yourself much time, frustration, and hair loss and call Diesel System Service/Achievement Marine. https://dieselsystemsllc.com/. They know their stuff on Kohler gensets, and can (hopefully) bring yours back to life.

Regards,

Pete
 
My honest thoughts on Kohler gensets are rather rude. Modern Kohler genset design seems to follow the kool aid of "auto-everything", implying that owners are idiots, and only Kohler knows best on how to start, monitor, and stop their gensets via microprocessor control, esoteric error codes behind hidden menus on LCD screens, and compounded by incorrect and misleading maintenance information. Making troubleshooting almost impossible for the average boat owner.

Having gotten that rant off my chest, I suggest you save yourself much time, frustration, and hair loss and call Diesel System Service/Achievement Marine. https://dieselsystemsllc.com/. They know their stuff on Kohler gensets, and can (hopefully) bring yours back to life.

Regards,

Pete


I would agree with you on this, overcomplicated for what it is. Parts are hard to get. If I had to pick a gen set based off my experience with this low hour unit, I would look at a different brand.
Thank you for the info on who to use, as Kohler's 1-800 number is useless.

Model 15EKOZD Serial SGM32FV59
Diesel
Single phase 15kw
 
Pete, thank you for the info for Diesel Systems, they said they do not have the access port of software to access the ECM module on the genset. But they suggested I pull part numbers off the temp sender and replace it next.
 
Hi RonR,

I'm assuming you have the operations manual and the parts list for your genset? If not, obviously the first place to start.

Sorry for no joy with Diesel Systems. They've been good to me, multiple times. Not sure why they would need access to the USB port to access the ECM. All the error codes are available via the LCD display on the genset itself. If it's like mine (a 6EKOD), the ECM can be manually reset from the control panel on the genset, after the fault (overtemp, in your case) is fixed (i.e.-the appropriate sensor is replaced). No need to access the ECM via the USB port.

And I'm equally unsure why you believe a previous Kohler tech might have "reset the computer" to an incorrect model? What gives you that hint? No "model information" need be accessed when the ECM is reset after a fault shutdown.

If your genset is similar to mine (a 2015-vintage 6EKOD), there will be both a temperature SWITCH and a temperature SENDER on the unit. One, or both, could be faulty, and the ECM will simply report an overtemp fault upon shutdown. I would suggest replacing BOTH sensors, resetting the error code, and trying again.

Sigh. I hate computers....

Regards,

Pete
 
Hi RonR,

I'm assuming you have the operations manual and the parts list for your genset? If not, obviously the first place to start.

Sorry for no joy with Diesel Systems. They've been good to me, multiple times. Not sure why they would need access to the USB port to access the ECM. All the error codes are available via the LCD display on the genset itself. If it's like mine (a 6EKOD), the ECM can be manually reset from the control panel on the genset, after the fault (overtemp, in your case) is fixed (i.e.-the appropriate sensor is replaced). No need to access the ECM via the USB port.

And I'm equally unsure why you believe a previous Kohler tech might have "reset the computer" to an incorrect model? What gives you that hint? No "model information" need be accessed when the ECM is reset after a fault shutdown.

If your genset is similar to mine (a 2015-vintage 6EKOD), there will be both a temperature SWITCH and a temperature SENDER on the unit. One, or both, could be faulty, and the ECM will simply report an overtemp fault upon shutdown. I would suggest replacing BOTH sensors, resetting the error code, and trying again.

Sigh. I hate computers....

Regards,

Pete

I do have the book, I did not know there were two temp units.
I do know how to reset the error codes and restart. But for some reason I have it in my head the ECM is thinking its too hot at 170 and shutting itself off. Thank you for the advise, I will order the two, replace and report back.
 
I have no idea if this is the case with your Kohler, but with a number of generators there are actually THREE temp devices.


One is the sensor for the temp gauge. Some generators monitor the reported temp and alarm/shutdown if over temp, but many do not.


The second sensor is a coolant temp switch. It's on or off, and trips if the coolant temp gets too high. When it trips, the generator will shutdown, and it may or may not tell you why.


The third sensor is an exhaust elbow temp switch, and like the coolant switch is on or off. If the exhaust elbow temp gets too high, the switch will shut down the generator, and may or may not tell you why it shut down.


If you have a service or repair manual you should be able to at least see what switches are present. The owners manual might have a wiring diagram that would tell you too.


If the temp gauge is reporting normal, then I would suspect the coolant temp switch or the exhaust temp switch is shutting down the engine. You could have a real over temp problem, or just a bad switch. When running, feel the exhaust elbow to see if it's hot. It shouldn't be. And if the temp gauge is normal and an IR gun agrees, then you just have a bad switch.


To figure out which one is shutting down the engine, disconnect them one at a time. If the engine keeps running with one of the switches disconnected, then you have found the problem.
 
are you sure your impeller is good
 
145F on the exhaust mixer is way above normal. Usually only 10-maybe 20F above sea temp. You might have a problem with sea water flow.
 
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