kohler 7.3ecd will not run


A

aussie

New member
The genset on my 2010 350SS will start and run rough for about 10 seconds then stop showing the UU code. The generator is a 7.3ecd fuel injected Kawasaki powered gas motor. I have had the Kohler agents out several times to look at it but they have had no luck finding the problem. They have changed the spark plugs, the ecm card, and the fuel injector, as well as testing the fuel pressure (55psi) and doing a compression test on the motor which was normal. They also changed the impellor and the water flow appears normal out the exhaust. Any help would be great, the genset has 80 hours on the clock.
 
Not sure how your genset is oriented, but on my 34 PC the heat exchanger faces fore and aft. The side facing the bow has a flow switch and a pressure switch for cooling water flow. The pressure switch is on the bottom 3rd of the end cap, thus accumulates debris, and plugs up. This causes the symptoms you describe, on my boat. It's a pain in the butt, because you are working blind, but remove and clean the pressure switch. I cleaned the flow switch as a bonus, as I had to remove the hose in order to get a wrench back there for the pressure switch. A test for this is unplugging the pressure switch, if the engine stays running perform the operation I've described.
 
I would not think that the flow switches would impact how it runs. Have you tried starting it with the main breaker off to see if it runs a bit better? It seems like it may be trying to start under load. Also the article that @jetmart shared has a post at the end that seems to match your symptoms where the relay needed to be replaced. I would take a look at that and it would likely be a cheap item to replace as well.
 
Tried starting the gen set with the main breaker off and with the pressure switch disconnected but no joy. Spoke to the Kohler service man and he is going to come down and change the crank angle sensor as this controls the timing for the spark to the plugs and the fuel injection timing. What relay are you referring to?
 
@aussie - here's a link to the service manual for that generator -
https://us.v-cdn.net/5020499/uploads/editor/mn/xb78fhfmi6gf.pdf
On page 35 you will see if talks about the K5 relay and all that it powers. I would say that if you have someone coming out to service, have them replace this relay as well. Its a cheap part (probably about $10) and there are many places where I have seen it referenced that these go bad over time including in the link to the Meridian forum posted above. In my opinion, swapping the crank position sensor is not going to do anything - they typically are good or bad and if bad the motor won't run at all.
I also find it interesting that these service guys aren't referring to the manual. It clearly shows what to check for the UU error code
 
Changed the K5 relay but made no difference. The Kohler dealer here is getting out of gas gen sets and repairing only diesel gen sets.
 
Another thought, happened to me and another Formula owner. There is a solenoid, coming off the fuel tank, mine failed, didn't open all the way, preventing adequate fuel flow. Check that to make sure you have good fuel pressure.
 
Thanks for your input, I think it may be fuel related but Kohler did check the fuel delivery pressure at the injector and it was 50psi
 
I had a similar issue with my Kohler 7.3ECD generator. FYI, Kohler wasn't very helpful, but I had done some troubleshooting. It seemed to be the O2 sensor. After purchasing an O2 sensor from marinepartssource.com, which did not fix the problem. I spoke to a generator tech with marine parts source and he told me if the ADC 2100 is working correctly, either it works or doesn't, there is 3 common part failures. 1) high temp shutoff switch (Kohler 249872), 2) coolant temp sensor (Kohler GM39601) or 3) oil pressure switch (Kohler 359789). He also mentioned that the Kohler fuel filter has a tendency to accumulate water after sitting for a while. He mentioned the filter was redesigned because of this problem (Kohler GM116125-S). He recommended changing the high temp shutoff switch first. I also changed the fuel filter. It has been running ever since. BTW don't forget to bleed the fuel system. I hope this helps.
 
Thanks for your input. Kohler has said its too difficult to troubleshoot with the generator in the boat so I have removed the generator from the boat and dropped it off at their workshop. They said to give them to Wednesday before ringing to see how they went. Hopefully they can fix the problem if not I will show them your reply as we need all the help we can to get this generator running.
 
An update on my generator. Kohler have had it for 3 weeks now and unable to fix it. Not sure what to do now perhaps look at Westerbeke?
 
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