Kohler 8kW Genset - Bleeding?

[Ndavies]

Hi All:
I have a Kohler 8kW Genset with about 200 hours on it. Its run great until recently it stopped - no noises, nothing unusual. I think it may have run out of fuel since the intake is apparently at a 1/4 tank (my guage was reading between 1/2 and 1/4). The engine cranks fine and sounds like it will start but just dies and never picks up. I am wondering if I have drawn air into the system while trying to start it. At the time, I didn't think it was out of fuel as I didn't realise the intake was set at 1/4 tank.

So, today I bled the low pressure side of the system per the instruction manual. I didn't see any major air, it seemed to pump out clean diesel fine. I have not bled the high pressure side as there was no suggestion to do this in the manual. Could this be my problem? Does anyone have similar experience or know of any other diagnostics I can try? I am not completely sure this was caused by low fuel, so I am also looking for other possibilities.

Thanks for any suggestions
Neil

[propellanttech]

Originally Posted by Ndavies

Hi All:
I have a Kohler 8kW Genset with about 200 hours on it. Its run great until recently it stopped - no noises, nothing unusual. I think it may have run out of fuel since the intake is apparently at a 1/4 tank (my guage was reading between 1/2 and 1/4). The engine cranks fine and sounds like it will start but just dies and never picks up. I am wondering if I have drawn air into the system while trying to start it. At the time, I didn't think it was out of fuel as I didn't realise the intake was set at 1/4 tank.

So, today I bled the low pressure side of the system per the instruction manual. I didn't see any major air, it seemed to pump out clean diesel fine. I have not bled the high pressure side as there was no suggestion to do this in the manual. Could this be my problem? Does anyone have similar experience or know of any other diagnostics I can try? I am not completely sure this was caused by low fuel, so I am also looking for other possibilities.

Thanks for any suggestions
Neil

My advice....

Check for water in the last (possibly only) fuel filter before it's injector pump. If that is ok, bleed the injectors.

James L

[bstreep]

We have an older Kohler 8kw genset. Ran it out of fuel a year ago, and tore my hair out getting it restarted. THEN I noticed a bleed screw on the injector pump (Yanmar diesel). It was the ONLY torn up screw on the engine - thus it became obvious that it is a common problem. I used a sharpie to put a note on it!

[ranger58sb]

Originally Posted by Ndavies

Hi All:
I have a Kohler 8kW Genset with about 200 hours on it. Its run great until recently it stopped - no noises, nothing unusual. I think it may have run out of fuel since the intake is apparently at a 1/4 tank (my guage was reading between 1/2 and 1/4). The engine cranks fine and sounds like it will start but just dies and never picks up. I am wondering if I have drawn air into the system while trying to start it. At the time, I didn't think it was out of fuel as I didn't realise the intake was set at 1/4 tank.

So, today I bled the low pressure side of the system per the instruction manual. I didn't see any major air, it seemed to pump out clean diesel fine. I have not bled the high pressure side as there was no suggestion to do this in the manual. Could this be my problem? Does anyone have similar experience or know of any other diagnostics I can try? I am not completely sure this was caused by low fuel, so I am also looking for other possibilities.

Thanks for any suggestions
Neil

Post your model number. If it's the same as ours (8EOZ), I'll take a look...

-Chris

[Dockhead]

I think we have the same generator.

Another idea based on my experience -- if the voltage is even a little low, the electric lift pump won't function, and the little Yanmar will start a little but then die.

So bleed it well and don't forget the bleed screw right on the injection pump (the manual shows all the bleed points). If necessary, crack the lines to the injectors right at the injectors to bleed the high pressure side. Make sure the battery is fully charged -- that could be your problem.

Failing that, change the filters and check the water separator -- make sure it's getting fuel. Rigging up a jury-rig fuel system is really easy on that engine -- good way to eliminate fuel system problems.

Good luck.

[propellanttech]

Originally Posted by bstreep

We have an older Kohler 8kw genset. Ran it out of fuel a year ago, and tore my hair out getting it restarted. THEN I noticed a bleed screw on the injector pump (Yanmar diesel). It was the ONLY torn up screw on the engine - thus it became obvious that it is a common problem. I used a sharpie to put a note on it!

Thanks for that information. It's something else I will store in my soft tissue for future use.

I've learned my new thing for the day!

James L

[capngeo]

Another "start but no run" problem is the oil pressure sensor. Most (if not all) generators have low oil and high temp shut down circuits. During cranking, the low oil shut down is disabled for obvious reasons. If the genny quits immediately upon release of the starter, I would also check this as well as the above fuel issues

[Ndavies]

Thanks all for the great suggestions. I'm new to diesel, so this is all very useful. I thought I bled all points shown in the manual. Maybe I got the one on the injector pump wrong as the diagram in the manual was poor. It said it was a screw, but at the point indicated mine seemed to have a bolt connecting the hose to the injector pump. I slackened this and got a good diesel flow(air free) when cranking. Maybe there is also a bleed screw that I missed. I also haven't tried loosening the lines at the injectors. I thought about the low oil pressure, and the manual suggested removing the wire to test this out. I think the pressure switch is just below the injector pump, so I pulled that off but it didn't fix anything. So, more things to try on my next trip to the boat which will be after thanksgiving. Happy turkey day everyone- and thanks again for the great suggestions.

[ranger58sb]

FWIW, on our model (8EOZ with a Yanmar 3TNE..74 I think...) the two bleed screws coming into and out of the secondary fuel filter actually face the engine. If I remember right, I think I used an L-shaped driver...

-Chris

[Panamajames]

I have the same Genset. It is wonderful. When it stops the reason I believe is this. The fuel comes from the main tank and when mine gets down to a little less than 1/4 the feed will not catch the fuel. Probably installed so your genset will not pick up the crude at the bottom of the fuel tank. I just add fuel and starts right up. This has happened several times and never had to bleed it. Good luck.

[Panamajames]

Also I have had it quit due to low oil. Just stops until you add more oil. What a great genset. Mine runs like a sewing machine.

[Ndavies]

Well I know you have all been on pins waiting to hear how this was all resolved-NOT!!


I spent a day bleeding everything that could be bled. Same thing- it tried to start then quit. So I removed the injector pump solenoid and it fired up and ran. Ha. Finally some progress. Then, I gave in and read the manual. I followed the troubleshooting decision trees and concluded it was the controller board. Ordered one, replaced it. Same thing. More troubleshooting and I found a wire in the control module with a spade connector hanging off. Replaced that, and it now runs like a charm. Not sure if it was that connection or the control board, but its now working and I'm happy. Thanks everyone for all the great suggestions!

[justlearnin]

Well now you know lots more about diesels. Isn't education FUN.

[Dockhead]

Originally Posted by Ndavies

Well I know you have all been on pins waiting to hear how this was all resolved-NOT!!


I spent a day bleeding everything that could be bled. Same thing- it tried to start then quit. So I removed the injector pump solenoid and it fired up and ran. Ha. Finally some progress. Then, I gave in and read the manual. I followed the troubleshooting decision trees and concluded it was the controller board. Ordered one, replaced it. Same thing. More troubleshooting and I found a wire in the control module with a spade connector hanging off. Replaced that, and it now runs like a charm. Not sure if it was that connection or the control board, but its now working and I'm happy. Thanks everyone for all the great suggestions!

Wow, that's really useful. I will file that away and hope I never need to know that.