Kohler 7.2ECD issues

jmauld

Well-Known Member
Jun 9, 2020
2,843
Carolina Beach
Boat Info
2010 Sundancer 390
2016 Sea Hunt Ultra 211
Engines
Twin 8.1l of gas guzzling iron
Edit: title should read 7.3ECD.

Is there a diagnostic manual which covers a rich condition with no error codes?

I can smell the fuel in the exhaust but the thing ran for an hour and a half tonight with no other problems.

Here’s has what has been replaced on it in the last twelve months. Roughly in this order starting with the most recent.


Injector
O2 sensor
Both Fuel pumps
Spark plugs
Plug wires
Raw water impeller

I see that there is a controller that is recommended to replace every two years. I have no records if it ever being replaced and this is my second year with the boat. I guess that will be my next attempt even though I think that has nothing to do with the fuel mixture.
 
I pulled the plugs tonight and found that one cylinder is fouling the plug. This narrows it down a bit. I’ll diagnose the ignition module on that side and do a compression check. I assume it’s possible that timing on that one cylinder could also be off.
 
I've got a 7.3 Kohler on my Chaparral and had a fuel smell issue in the exhaust back in 2019. Here's the diagnosis from my mechanic at the time. Haven't had issues with it since.

"Diagnosis of the generator running smells like fuel. Found that it was only running on one cylinder. The front ignition coil was not firing. replaced coil and smell is no longer present."
 
Thank you. I am hoping this will finally solve the issue.
 
Oh my god, this thing is going to be the death of me.

replaced the ignition coil tonight and I “THINK” it has cleared up the running rich issue. However, now the thing is overheating. Raw water flow seems to be good and that water is coming out of the exhaust lukewarm. But the motor is definitely running hot and it’s spewing coolant from somewhere.

Tired for tonight. I’ll pull the plug tomorrow and check for any signs of water on the plug and then run it to see if I can find where the coolant is spewing from.
 
Oh my god, this thing is going to be the death of me.

replaced the ignition coil tonight and I “THINK” it has cleared up the running rich issue. However, now the thing is overheating. Raw water flow seems to be good and that water is coming out of the exhaust lukewarm. But the motor is definitely running hot and it’s spewing coolant from somewhere.

Tired for tonight. I’ll pull the plug tomorrow and check for any signs of water on the plug and then run it to see if I can find where the coolant is spewing from.

Oh man, that is crazy. Hope you're able to resolve.
 
Okay, I kind of wimped out on working on the generator during these recent dog days. But started back on it today, by burping the cooling system and letting it heat up.

Temps very quickly reached 210F and then slowly crept up to 220 where I shut it down. I was concerned that I might’ve had a blown head gasket, but I don’t think that’s the case. I think it just overheated the last time I ran it and boiled into the overflow tank.

I’ve ordered a new pressure cap and thermostat.

I’ve seen a bunch of people mention flushing out the exchanger. Have any of you replaced it with a new one or one from MrCool. I assume after 13 years of saltwater that it’s probably near EOL?
 
Pulled the heat exchanger off tonight. Good lord that rear bottom bolt is a PITA. Any tips on getting this thing back in place, or will I need to do more disassembly to get to a point where it will go back on?

why isn’t this one hole slotted, which would make installation/removal considerably easier.
 
I got that stupid bolt back in. The generator seems to be holding a steady 199 F with various loads on it.

Is there a “coolant bleed procedure” anywhere? Perhaps I shouldn’t try bleeding it since it’s holding a steady temp.
 
There is a small bleed bolt on top of the exhaust manifold towards the outboard side of the genny. Remove it while you have the cap off and are topping off the coolant.
 
There is a small bleed bolt on top of the exhaust manifold towards the outboard side of the genny. Remove it while you have the cap off and are topping off the coolant.
Here’s what I did.

I opened that port that you mentioned while a I filled the coolant. Started the generator and let it run until coolant started coming out of both the fill hole and that bleed hole. Closed the bleed hole and then closed the fill hole. Then I filled the overflow canister.
 
So is the genny running and staying cool now?
Yes. It’s hovering between 197 and 201 with varying loads on it

at this point I’m just wanting to make sure I do a complete job before putting the silencing cabinet back together. I can‘t really thoroughly test it until next summer when water temps are back up.

edit: I probably should just close it up and move on to the next thing.
 

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