Onan 7KW genset help

[viper]

I have a friend that has a '95 Bounder with the above genset. It will start fine and run for about 10-20 sec. and then die-just like you hit the "kill" switch. It will restart fine and then run again for the same about of time and die. He checked the fuel line into the genset carb. and that line pumps plenty of gas to the carb. The gas tank is 3/4 full of gas, so it is well above the 1/4 low gas limit to stop the genset. Any ideas if it has plenty of gas in the tank, and plenty of fuel at the carb. gas inlet-why it keeps dying? Maybe the gas limit switch that controls the fuel level in the tank that stops the genset is faulty, and actually reading "low" when there's ample gas in the tank to run?? Anyway to check this? Thanks for your help.

[The General]

Viper,

Sure sounds like a lack of fuel coming to the gen.
Fuel in fuel line and then fuel is consumed by gene but fuel cannot keep up with gen. demand therfore dies.
I believe the gen. fuel tube that is in your gas tank is positioned to 1/4 tank level and has no gas limit switch.
I would disconnect fuel hose at gen. and connect another to a can of fuel
to prove or disprove that he has a cracked rubber hose and consequently air sucked into the old line and fuel starvation.
Check fuel filter maintenance and proper altitude knob adjustment and crankcase for proper oil level and if it's low there is a built-in cutoff switch that will stop the gen. Be aware that the fuel pump can also fail.


Steve

[viper]

Thanks for your ideas , Steve-I'll pass them along to the owner.

[Gary RVRoamer]

Low oil pressure will also cause a shutdown like that. Has he checked the oil? Filter changed recently?

[viper]

Thanks Gary- yes-- oil was changed along with oil filter.

[4Knights]

Could be many things. Look under the files section of the IRV2 site I uploaded the service manual for this generator.

[ga traveler]

Your generator uses 12v from the start circuit to start and run while cranking. when you release the start button, the board should provide 12V to keep it running. Try starting the gen and holding the start button in and see if it runs while you hold the start button in. If it runs while you hold it in and quits as soon as you release it, you have a starting point to trouble shoot. Since the oil has just been changed, make sure it is at the correct level Too much or too little oil will shut it down. If the oil level is OK, The next thing to check would be the board. Your best bet is to borrow a known good board from a friend who has the same board. Be careful! most of the boards look the same, but they don't work the same. It has to be the same number.

[RJay]

viper,
Maybe this will help.

Q. Why does my generator start and then shut down as soon as the start switch is released?
A. Most models require both oil pressure and AC voltage from the generator to keep running. A lack of AC voltage can be caused by a variety of problems involving the control board, regulator, generator and wiring. A stuck oil pressure switch can also cause this symptom. The interaction between the various components of the system can be confusing during troubleshooting. Use the Troubleshooting Guide to isolate the problem.


Q. My generator starts OK, runs for a while and then shuts down. Sometimes, it can be re-started after cooling for a few minutes. What causes this?
A. The most likely cause is fuel starvation. This can be caused by low fuel level (not getting gas), vapor lock (too hot, gas is boiling), fuel contamination (water or dirt in fuel and/or filter) or a faulty fuel pump (insufficient fuel pressure). Models equipped with low oil level (LOL) switches will shut down the engine on low oil level.

[Elkhartjim]

I had the same situation. It was a bad connection at the battery. Cleaned, tightened connection with no more problems.

[4Knights]

Another item to consider that has not been mentioned is mice or pack rat damage to your wiring. One wire chewed or broken will create A non running condition. This happened to me and after many hours of trouble shooting with the multimeter, a mirror and flash light I found the wire all the way at the back rear of the set chewed. Local shop wanted huge money and 10 hours time to diagnose.

Please download the troubleshooting/service manual I uploaded on the files section of this site. If you plan on dropping the genset get some help and be careful.

Like the others have stated check the obvious first- vehicle on level ground, oil level at correct amount, full battery charge, 3/4 tank of gas minimum as not all gauges are close to correct, grounding strap clean and secure. Then start the diagnosis. Let us know where you're at and what you have done in order so we can provide more help.
Ron

[viper]

Thank you all for your continued suggestions-I'll pass them along to the owner. He hasn't had the time to get into this yet, but he will- and I'll pass along his findings when he finds the problem. Your help is greatly appreciated.