8eoz kohler genset shuts down with too much load after it heats up

[coin operated]

genset starts every time and runs perfect, when started after sitting all night can turn on both a/c's water heater etc, after 15-20 mins genset shuts down, genset starts right back but then will only run with light loads on it, if no load will run all day, replaced electric fuel pump, and filters, plenty of oil pressure, plenty of water flow, and not overheating, has something to do with the amount of load, possible govenor or control board???. please i need all of the expertise you guys have. any help would be greatly appreciated.

[REBrueckner]

How do you know it's not overheating??

Still, it could be a defective overheat sensor: first thing I'd do is bypass or disconnect (depending on how they are wired) any overheat shutdown sensors and see if it keeps running.

Is this a gas generator? I'm guessing when the unit shuts down, it does so immediately, as when you manually shut it down?? Then it starts right back immediately w/o any cool down time?? Then seems like it's an electrical shutdown of some sort...via elimination of spark. If it's a fuel problem or shortage, it would typically slow down gradually, sputter and cough for maybe five or ten seconds...trying to run at slower rpm.

This will sound weird, but check any fuse and holder that supplies your controls on the genny with power. An Onan gen. had a similar problem...turns out the fuse spring was defective!!!...would loosen when current warmed it up and apparently lost tension...story was posted by Bill Allen and I was aboard his boat unsuccessfully trying to trouble shoot the problem. Why that genny restarted promptly I don't think we ever figured out.

[yachtsmanbill]

My 42 year old Onan MCCK shuts down like that if its low on oil. Yes, it does leak outa the case halves joint... Sounds like youve got a sensitive temp or oil pressure switch... UNLESS, its shutting down from a generator overheat. (?) ws

[Boatsb]

Hey Reb why would it run with a light load but not a full one if it is overheating? From the description it will continue to run as long as the load is light but not under full load. That's probably the electronic controls or fuel but it's hard to diagnose remotely. Especially without a manual.

Sometimes free advice is worth what you paid for it.

[coin operated]

genset is diesel, boatsb is correct genset will run all day with light load, or no load, genset has remote panel plenty of oil pressure, removed sound shield place my hand on exhaust elbow, cool to the touch, if any shut down sensor was faulty it would not run all day, with light load, what makes me think it might be control board problem is when after sitting all night, i can turn everything on in boat and genset stays running for about 20 mins. no fuses on this genset, just (1) circuit breaker loacated on start panel, if circuit breaker is tripped engine does not even crank over, please more help would be great.

[Boatsb]

Do you have a manual? If not get one asap

[Boatsb]

Also there could be an issue with the windings and the generator end with heat comes expansion.

[coin operated]

have manual online pdf, have read it not much help, went back out to boat, no more than 1 1/2 hour elapsed, started genset turned hot water heater, battery charger, 2 burner cooktop on high genset ran perfect, did not let run long, maybe voltage regulator????? if there was a problem with windings, would it not just stop generating 110 volts but should not kill motor.

[Trojan]

I would look at the fuel shut off solenoid. From what you say, It appears to be a heat related issue. Watch the fuel shutoff solenoid. It may take a while to see anything happen. Coils are famous for opening when hot and closing after cooling. It may be the place where the coil is mounted is getting warmer after the motor comes up to full temp. If that is not the problem look for a coil that must be energized to run. It's got all the systems of a bad coil. There a pain in the butt to find. You might use an IR heat gun and start checking temps in areas where there is a spring or coil controlling the operation.

BILL

[Boatsb]

have manual online pdf, have read it not much help, went back out to boat, no more than 1 1/2 hour elapsed, started genset turned hot water heater, battery charger, 2 burner cooktop on high genset ran perfect, did not let run long, maybe voltage regulator????? if there was a problem with windings, would it not just stop generating 110 volts but should not kill motor.

It may trip a safety circuit and shut off the system from the control board. Again I would look at the schematics and see what controls what.


When it is running bypass each electronic safety circuit one at a time and see if it handles full load. Also check the fuel solenoid and fuel pressure. heavy loads require more fuel.... It could have a simple electrical issue