Kohler Generator Won't Start... Sorta

trush

New Member
Nov 4, 2015
25
Allen, TX
Boat Info
40 Sundancer 2008
Engines
MerCruiser 8.1S Horizons w/ V-drives
Hey gang... I'm having some strange behavior with the starting of my Kohler 7.3ECD generator. Historically, this EFI generator will start right away. Over the last couple of weeks, its been behaving very strange.

After setting unused for a week, it will crank over and run thru three separate starting cycles without firing. It throws an "over crank" error. I'll reset the error and leave it alone until the next day. It will fire up just fine, on the first try, the next day?!?! It continues to start on the first try the remainder of the day.

The following weekend, starts the same cycle again. Won't fire after three attempts, but will fire on the first try the next day.

It has fresh plugs and oil as well as a new fuel/water separator filter.

Anybody else seen anything like this?
 
After looking thru some older threads related to Kohler, I realized that I haven’t changed the inline fuel filter. I’m gonna try that next and will post results.
 
Well, still back to the same issue... I changed the inline fuel filter, but it's still doing the same thing. Won't start after multiple attempts, but will fire on the first attempt the next day. So weird!?!?
 
When you replaced the fuel / water separator filter, this allowed air to be induced into the fuel system for the generator. (I know this from previous experience) Read in your owners manual, or can be viewed online on how to bleed the fuel system. It is a fairly simple procedure. This will solve your problem.

Bill
 
I just bled the fuel lines yesterday on my kohler 5ECD, super easy, although holding down the select button the entire time, AND holding the bleed tool on the valve, and holding the bottle at the end of the hose to capture the gas was a bit tricky.
 
Thanks for the ideas. This makes sense and I'll give it a try the next time I'm at the boat.
 
Well sadly, the fuel bleed didn't solve the problem... This seemed like a likely cause, but its still acting the same. However, I did have an observation that I don't know if it's normal or not.

I was able to get good fuel flow from the top schrader valve per the bleed instructions. And since there's another valve in the fuel pump area (lower right corner), I figured I'd bleed that one too. However, I was not able to get any fuel flow from this valve. The bleed instructions didn't mention anything about this lower schrader valve, so I'm not sure if its has the same purpose.

Does anyone know if fuel should've flowed from this valve? If yes, does this highlight a potential problem?
 
As luck would have it, I started searching for “Kohler Generator forums” on FB, and found one!
I posted my question and 15 year veteran of exclusive Kohle generator repair replied.
This guy really knows his stuff and told me what to do. He is in Athens Greece! (Small world after all!) I keep you all posted!
 
As luck would have it, I started searching for “Kohler Generator forums” on FB, and found one!
I posted my question and 15 year veteran of exclusive Kohle generator repair replied.
This guy really knows his stuff and told me what to do. He is in Athens Greece! (Small world after all!) I keep you all posted!

What did he suggest?

MM
 
80% chance its the RIB board he said. Although, Ive tested it pretty well.....I ordered a new one.
Then he told me some techniques to try, to test the adc2100. To bad it’s been in the lower 30’s this week! Tomorrow is a possibility, though.
 
I have had to start my 5kw the same way since we bought our 340. Like clock work, it takes (3) 5 - 10 second cranks a few seconds apart. Usually starts on the 4th, but sometimes the 5th try. Seems to lose its prime after a few days on non use. After initial start, cranks right up the rest of the day or weekend. have read on these forums that this is not abnormal for Kohlers.
 
Just a quick update on my issue, in the event that this will help someone else in the future... My solution was to replace the ECM. Once the ECM was replaced, it's back to starting on the first attempt!
 
Thanks for the update. Isn't there two electronic boards in there? Which one did you replace, the front panel with the displays? Kind of hard to imagine a bad ECM causing this.

I also have found the shrader valve on the fuel pump does not let any gas out. I completely unscrewed it and still no gas. I was also worried something was clogged, so I'm glad you posted this. This appears to be normal.
 
I refer to the front board, with the display, as the Advanced Digital Controller (ADC). On the back side of the generator is a black box with a large wiring harness, the Electronic (or Engine?) Control Module (ECM). This is the one that was causing my issues.

On your fuel bleed, are you following the instructions on engaging the fuel pump, while having a fuel bleed tool on the shrader value? I made my own bleed tool by purchasing a pneumatic tire chuck (on a long stem), and then added about two feet of plastic hose to the end of the chuck to put into a bottle to catch the fuel.
 
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Yes, I can bleed the shrader valve at the throttle housing using normal bleed procedure. When I did this on the shrader valve out of the fuel cooler pump I got nothing. It was bone dry. My fuel cooler pump is in rough shape, it has pretty bad corrosion so that is why I wasn't sure if this was normal or not. If I can't get mine running this is the first thing I'm replacing.

For our own benefit we should see if this is normal, as well as test the nominal fuel pressure at the throttle body - in working conditions.

How did you come to the conclusion that the ECM needed to be replaced?
 
Just a guess, but I don't think that the lower shrader bleeds. Like you, my top valve bled fine, but nothing from the lower one. Therefore, I think this is normal.

Interesting story on the ECM.... After talking to several folks and having a couple of techs come to the boat, the consensus was the ECM. One tech had an ADC, so we put that in, programmed it, but it still didn't have any spark, so we swapped it back out and assumed it was the ECM. At this point, pretty much the only thing that we didn't rule out.

I should also mention that when I started this thread, the gen would start occasionally, but not consistently. In Dec, it would not spark at all and never started again. Cranked fine, had fuel, but no spark. Had a tool on the spark plug that had a clear bowl that would show when the coils had spark. Nothing, on either cylinder....

So, I ordered an ECM from an online Kohler authorized reseller, put that in, and ...... nothing. Still no spark... Ugh!

Not knowing what else to do, I pulled the generator from the boat and took it to a shop that specialized in generator repairs. A challenging job for sure, but not as bad as I expected. The repair shop has a great reputation, but they will not do any work on a boat, you have to bring it to them. I boat on a lake and not near the coast, so repair options are much more limited here.

They put a new ECM on and it fired right up!!! Turns out that the ECM that I got was defective. The online retailer was awesome and gave me a full refund on the defective ECM.

In hindsight, I'm very glad that I ended up taking the generator to a shop, because, also unknown to me, the valves were out of spec causing one cylinder to only have half of the normal PSI. They went thru the entire generator and made sure that everything was in spec and tuned properly.

She's never ran nor sounded better!
 
Great information, thanks. Now I see with no spark how you started to narrow down to ECM. Slight chance it could have been an electrical contact issue that perhaps cleaning up the connections to the 2nd ECM fixed the problem. Either way, be glad its working. It's a little confusing what functions the ECM vs ADC electronics perform.

I also pulled my generator out. Planning to try to start it in a week or so. I'll eventually make a video how to even wire it outside of boat since it requires battery from the external connector and maybe could help someone in the future.

However I didn't pull the muffler. Did the shop run it with no muffler? I assume it will be loud but hopefully it doesn't require some sort of back pressure and it will run ok.
 

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