I have a Onan 7000 gen with 805 hours on it, on our 1999 coachmen Santara, when I start the gen it takes a minuet or two until it kicks on, which it always has, but then it will produce power for maybe 5 minuets and then the power shuts off. The gen is still running but there is no power.
I have checked the circuit breakers and they are still set. I can shut the gen off and start it up again and sometimes the power will come on again and sometimes it wont.
I have taken all the quick connectors apart that I can see with the access door open, and re-connected them after putting the wax like stuff on them to prevent corrosion.
Where do I start trouble shooting? What do I need to look for? (besides an onan dealer.)

You say the power comes on after a minute or two. Is there a transfer switch involved? If so, that may be the problem.

Yes there is a transfer switch, it generally takes a min or two before it "clicks" and the power comes on in the rig. it "clicks when I plug into electric too just like it does after the gen has run for a min or two.

Just to build a bit on RIF's post, I assume your genset has some plug connectors on the face of it. If so you should plug something into one of those when the genset is misbehaving. That will help determine whether the problem is on the genset or in the coach wiring.

Transfer switches are notorious for failing. Based on the symptoms you describe it is the first place I would look. You should be able to remove the cover and check the voltage with a meter. There should be a line in from the generator, a line from shore power, and a line out to the main breaker panel. The schematic is often on the inside of the cover.

No 110 plug on the genset that I can see.
I will dig out a meter to check the transfer box after the rains quit.

You are correct that your Onan will not have any outlets on it. RJ is thinking of the portable sets that trailer owners use.

I tend to think those who suspect the transfer device are on the right track. Onan generators are designed such that if they are no putting out any power they will stop running as soon as the operator releases the spring loaded start switch. Since yours continues to run, I think that it is putting out power but for some reason it is not reaching your power distribution panel.

Your Onan will have two circuit breakers physically mounted on it, somewhere. I would also try opening them and then reclosing them just to be sure.

The first place that I would check is once your power has failed from the genset, check for proper voltages on the genset input on your transfer device. But be careful! A 7KW set has 240V between the two hot legs, 120V from either hot leg to neutral or ground.

My Marquis 7000 produces 56.7 amps at 120 volts not 240. The 2 legs are not out of phase.

OK do I set the multi meter at 240, or 120? I will check my book on the gen before I test it to avoid any possible errors. ( if it says in the book I have)

If your meter is not self sensing I would set it to the 240 scale. You will still see 120 register half way up the scale if that is the voltage, which it will be unless you do have 240 and are checking across the two hot legs. When checking from either hot to ground or neutral you should see 120. If you see nothing between the two hot legs then your gen is like James said and just produces 120.

Joe,

Jamey might be right, come to think of it, I have never checked phase to phase on my 5.5KW Onan and it very well could be. I guess I should check that out. It is a habit of long standing when you have two hots to think in terms of 240V between them but in an RV it really doesn't matter, other than for safety reasons. As I think of it, I'm pretty sure that Jamey is correct that Onans only make one phase, but split it for the larger size generators.

If your meter is set to accept 240V, it will also register 120V as most meters have a wide enough range to read both. Just to be sure, use the higher one first, as that will protect the meter and you can always step down a scale.

The other reason to use the higher scale first is that should you read across 50A shore power, I assure you that it will be 240V and so your meter is protected.

Thanks for all the information, I went to test my multimeter and....well lets just say I will be buying a new one in the near future, so the gen has been put on hold for a few days.
I guess I'll have to stay where it is cool enough that we don't need the AC, or be plugged in.

Hi Joe

Unless you let the smoke out of the meter, it may just be a fuse in the meter itself. Many meters have them.

Dave O

I think it is a 9v battery and the need for new wires, I'll pick up a new/better one between the east coast of VA and KY this week sometime.

quote:

Originally posted by JoeandMarcia:
I think it is a 9v battery and the need for new wires, I'll pick up a new/better one between the east coast of VA and KY this week sometime.

Get a Fluke true RMS meter.You will never have to buy another..