Now my generator is acting up!

Hellman Huddle

Hellman Huddle

New Member
Nov 6, 2009
510
Lake Wateree/SC Coast
Boat Info
2005 260 Sundancer
2000 F-350 Diesel
Engines
350 Mercruiser Bravo III
If it ain't one thing it's another, gotta love it. Anyway, now my genny (Kohler 5E) runs for 10 minutes and shuts down.

I have good water flow out the exhaust, impellar was chaged a couple months ago.

Oil level is good and just changed.

Coolant level is good and freshly changed.

ANy Ideas?

I did read some post about an "oil sending unit" not sure where it is, something about disconnecting wire and if it ran after that replace it.


:smt100:smt100:smt100:smt100:smt100
 
If the thermostat is not opening up and allowing the engone to get too hot, that will cause it to shut down too. The impeller could still be working great and pumping water well, but if the thermostat doesn't open, the engine cooling water doesn't go into the heat exchanger while raw water does its normal thing and exits out the exhaust and then the engine will overheat and the high temp switch will shut is down.
You can also check the oil pressure shut down an easier way. When you initially start the engine, normally you have to hold the run or prime or choke switch (whatever it is called on your genny) for a few seconds after it starts. This bypasses the low oil pressure switch because it can take several seconds to build up pressure after a start. So now, if immediately after it quits, you can restart and it stay running as long as you hold the run switch down, but stops when you release it, then that could be a low oil pressure switch problem.
 
Last edited:
docofthebay said:
If the thermostat is not opening up and allowing the engone to get too hot, that will cause it to shut down too. The impeller could still be working great and pumping water well, but if the thermostat doesn't open, the engine cooling water doesn't go into the heat exchanger while raw water does its normal thing and exits out the exhaust and then the engine will overheat and the high temp switch will shut is down.
You can also check the oil pressure shut down an easier way. When you initially start the engine, normally you have to hold the run or prime or choke switch (whatever it is called on your genny) for a few seconds after it starts. This bypasses the low oil pressure switch because it can take several seconds to build up pressure after a start. So now, if immediately after it quits, you can restart and it stay running as long as you hold the run switch down, but stops when you release it, then that could be a low oil pressure switch problem.
Click to expand...

Ok, I don't think it is oil pressure now. I found the oil sender and it is still shutting down. I leaning towards the high temp. ANy idea where the thermostat is located?
 
Did you bleed the air out of the system when you change the antifreeze? the 5e tend to air locked.
 
gyrospiro said:
Did you bleed the air out of the system when you change the antifreeze? the 5e tend to air locked.
Click to expand...

I think this is most likely your problem if you recently changed your coolant.
 
gyrospiro said:
Did you bleed the air out of the system when you change the antifreeze? the 5e tend to air locked.
Click to expand...

Can someone explain the procedure to bleed the air out of the system? It does not say how to do it in the service manual either.

Thanks
 
Based upon this potential for coolant air lock, I am now wondering if I really need to change the coolant over the winter. The coolant has been in there for 5 years but the PO put less than 5 hours total on the generator before I bought the boat. It now has 48 hours because I ran it every time I went out. In these circumstances, do I really need to change the coolant with so little prior use? I don't want to have to pay my marina mechanic 1 or 2 hours in addition the the normal time to change the coolant just to bleed the air out of the system if I can wait another season.
 
YES!!
Why Change Antifreeze/Coolant yearly?
Antifreeze/coolant experts have a warning for those neglecting their cooling systems. Most people have some idea that antifreeze/coolant helps prevent the radiator and cooling system from freezing up or boiling over. Few people understand that coolant also contains special chemical additives to prevent serious damage from rust and corrosion. However, over time, the additives wear out. This depleted coolant becomes acidic and can actually corrode the metals in the cooling system. And here's where your trouble often starts.
 
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I am having similar problems. My 5KW performed as described during survey. The surveyor suggested it might need a tune-up. In August my service guys did tune-up, replaced impeller, cleared an air lock, and corrected the antifreeze concentration level. This worked correctly for about 10 hrs. Then it started performing similarly to the OP’s again.

My service guys found small bits of impeller in the fresh water discharge when they winterized it. They want to remove the heat exchanger and completely clear it of that debris. They believe bits of impeller float around the in the heat exchanger until enough of them stick in the cooling tubes restricting cooling. They also said you may still think outflow is good while not getting adequate cooling. The Kohler is said to run on the hot side anyway when working properly, so the margin for heat increase to overheat is small, meaning a small restriction could cause a big problem.

They have done this in the past and had good results. They also said if an impeller breaks up, when it is replaced they try to find all pieces. If they cannot they will then do the heat exchanger. Since I just purchased this we do not know the history, but have evidence of the impeller debris. I plan to replace the impeller and the impeller housing???.

Has the impeller broken at all in the past?

Can air lock just occur on it’s own after working for 10 hrs?

Don’t intend to hijack your thread but if any of you have thoughts on this let me know.

MM
 
Last edited:
MonacoMike said:
I am having similar problems. My 5KW performed as described during survey. The surveyor suggested it might need a tune-up. In August my service guys did tune-up, replaced impeller, cleared an air lock, and corrected the antifreeze concentration level. This worked correctly for about 10 hrs. Then it started performing similarly to the OP’s again.

My service guys found small bits of impeller in the antifreeze when they winterized it. They want to remove the heat exchanger and completely clear it of that debris. They believe bits of impeller float around the in the heat exchanger until enough of them stick in the cooling tubes restricting cooling. They also said you may still think outflow is good while not getting adequate cooling. The Kohler is said to run on the hot side anyway when working properly, so the margin for heat increase to overheat is small, meaning a small restriction could cause a big problem.

They have done this in the past and had good results. They also said if an impeller breaks up, when it is replaced they try to find all pieces. If they cannot they will then do the heat exchanger. Since I just purchased this we do not know the history, but have evidence of the impeller debris. I plan to replace the impeller and the impeller housing???.

Has the impeller broken at all in the past?

Can air lock just occur on it’s own after working for 10 hrs?

Don’t intend to hijack your thread but if any of you have thoughts on this let me know.

MM
Click to expand...

I replaced the impeller back in July and yes it was in pieces, not sure if I got it all or not.
 
I pulled the thermostat out and put it in boiling water. It barely opened. I also noticed there was no fluid in the heat exchanger when I opened it up. I hope this is it. Thermostat is on order.

Any thoughts?
 
MonacoMike said:
I am having similar problems. My 5KW performed as described during survey. The surveyor suggested it might need a tune-up. In August my service guys did tune-up, replaced impeller, cleared an air lock, and corrected the antifreeze concentration level. This worked correctly for about 10 hrs. Then it started performing similarly to the OP’s again.

My service guys found small bits of impeller in the antifreeze when they winterized it. They want to remove the heat exchanger and completely clear it of that debris. They believe bits of impeller float around the in the heat exchanger until enough of them stick in the cooling tubes restricting cooling. They also said you may still think outflow is good while not getting adequate cooling. The Kohler is said to run on the hot side anyway when working properly, so the margin for heat increase to overheat is small, meaning a small restriction could cause a big problem.

They have done this in the past and had good results. They also said if an impeller breaks up, when it is replaced they try to find all pieces. If they cannot they will then do the heat exchanger. Since I just purchased this we do not know the history, but have evidence of the impeller debris. I plan to replace the impeller and the impeller housing???.

Has the impeller broken at all in the past?

Can air lock just occur on it’s own after working for 10 hrs?

Don’t intend to hijack your thread but if any of you have thoughts on this let me know.

MM
Click to expand...

Hey MM,
After studyning the service manual and how the cooling system works, I don't see how impeller pieces can get into the anti-freeze. The fresh water goes through coils in the heat exchanger and the anti-freeze mixture circulates theough without contact to the fresh water. The only way impeller pieces could get in would be if you had a hole in one of the coils. In this case you would need a new Heat Exchanger.

Am I correct in how this thing works?

thanks
HH
 
Herman, You are correct and I did not type what I meant. (Since corrected). The impeller bits plug the fresh water side, not the antifreeze side.

I suspect the heat exchanger gets blocked, causing minor overheating, resulting in antifreeze being belched out. Then causing the air lock and overheating severe enough to trigger the shut down.

I still want to know if air lock can just pop up on a unit that has ran fine for 10 hrs, or is there something that had to change?

I had hoped some of the smart ones would have opined before I posted this, but tell us what you think.

MM
 
Last edited:
MonacoMike said:
Herman, You are correct and I did not type what I meant. (Since corrected). The impeller bits plug the fresh water side, not the antifreeze side.

I suspect the heat exchanger gets blocked, causing minor overheating, resulting in antifreeze being belched out. Then causing the air lock and overheating severe enough to trigger the shut down.

I still want to know if air lock can just pop up on a unit that has ran fine for 10 hrs, or is there something that had to change?

I had hoped some of the smart ones would have opined before I posted this, but tell us what you think.

MM
Click to expand...

Mine was shutting down before I changed the fluid. When the thermostat comes in, I am going to take the heat exchanger off and blow it out. I am still not sure about this air lock thing. It seems to me you could run the generator with the radiator cap off and allow it to come up to temperature (THermostat opens) and that would perge all of the air out of the system.
 
Interesting idea. I'll ask about it. I still want to know what could cause air lock once the system is sealed and functioning.

MM
 
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