Generator shuts off after 30 minutes

Started by denisondc, November 02, 2009, 07:36 PM

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Sent: 7/5/2003

The onan 2.7 KW genset on my 72 will run for hours unloaded, or will run the a.c. fine for about 20 to 30 minutes. Then it shuts off, just as if I was holding the kill-switch down. No sputtering or hunting or dropping rpm; it just coasts to a stop. It seems to have fuel, and always restarts nicely after an hours rest. Its the original genset, and as far as I know has all original parts. I suspect the ignition capacitor has reached its end-of-life, and am hoping it isn't behind the flywheel, like on the lawnmowers.

Has anyone had this problem, and can you give me any insight? It was in the lower 90's today, so with the sun on the roof a.c. the genset would have had a heavy load; but years ago it would handle the load in equally hot temperatures, and now it isnt doing very well. denison

Tarsand traveler

Sent: 7/5/2003 8:17 PM

I think you're on the right track in the ignition system. I'd check the coil as I've seen similar behaviour in cars and it turned out to be the coil. It would run fine for a while from a cold start up then quit when it warmed up.
  Good Luck


Sent: 7/5/2003 8:37 PM

Another thing you could check is whether your unit has a high temp cutoff switch, mine does, what it does is shut off the ignition if the unit overheats, thus preventing a fire or damage to the unit. the switch on mine is located in the side of the case. if yours is restarting after a chance to cool off, i doubt the switch is bad, as a defective switch usually won't reset itself after a shutdown condition.

A better bet is that it has been years since anyone has removed the air ducts (the sheetmetal over the heads) and cleaned the usual debris (dirtdauber nests, leaves, etc...) out from the cooling fins cast into the heads. hope this helps.-- lefty 

p.s. when's the last time you cleaned your a.c. unit (condenser fins and the inside filter) ? a clogged unit uses much more current
I reserve the right to reject your reality and substitute my own...


Sent: 7/6/2003 8:16 AM

My a.c. has only been up there for 4 years, but warrants cleaning certainly. I imagine there is 31 years worth of dirt in the genset; all original and vintage dirt. I will be pulling the genset out pretty soon to un-do its sheet metal. Thanks for the ideas - and why didn't I think of them. No answer needed. denison

Rick Shaw

Sent: 7/7/2003 8:53 AM

I would have trouble like this with my a/c on hot days.   Seems that you must keep the oil level at a constant.  Also there are variables involved with which oil you use.   I would choose the heaviest viscosity oil for the very hot days.   

My generator would shut down on a hot day.....I would check everything and then realize that an air cooled generator in a very small space heats up very quickly. 

You should run your generator with the compartment door open all the way so that you can get all the air possible.   You could even install a fan blowing on the genny to help keep it cool.   

On the hot days of summer you use more oil than normal.   After filling oil to the proper level.....the genny would start again and the a/c would work normally.


Sent: 8/4/2003 7:13 PM

Hay I'm not expert but on my Owan 3.0 it has a fuel cut oft selnoid vlv in line after the fuel pump. My generator stop running and I found out that the selnoid vlv was clossing because of not enough juice to keep it open. I ran a hot lead to the solenoid and I could hear the valve open and shut, you might just test this valve as it is easy to check out. Jipjob


Sent: 8/6/2003 9:26 PM

    Have you got your problem here fixed?
If not I suggest to make a heat shield to try between fuel line & exaust if they are in the same area or close to each other my friends had an exaust leak & was doing the same thing!
       hope this will help.



Sent: 8/6/2003 9:40 PM

I havent gotten to fix that yet, since I probably wont be needing it again this year, and have to get to work on replacing the roof of my other winny, before I have to replace its walls and floor too.
My genset doesn't seem to have any solenoid valves in its fuel system, and the exhaust is on the far side of the unit - the backside- from the fuel pump and carb, which is on the outside, next to the door. I did find that the 120V cable isn't long enough for me to pull the tray all the way out! denison