Onan info

[Jeff Niceswanger]

Hi Rich,
A little info would be appreciated. We are just about to take our unit to the dealer but if there is something we could easily look at before we throw in the towel it would help. We have a 4000 Onan micro in a 2004 31 foot Four Winds( Serial #H020405714 Model 4KYFA26100K Spec K with 1500 Hrs.) and @ Columbus points race the starter drive busted in half. We dropped the unit out of motor home,ran to the Columbus Cummins dealer picked one up and changed it .Many busted pieces were throughout the shroud,so we took it all apart ,cleaned it all out, and re-installed everything. It took right off, and ran that whole day,but 24 hours later(next morning) it fails to start and sets a code 14(Over Frequency). It will run as long as you hold in the Start Button,and will run when its stone cold for about 30 seconds before it powers down. During this 30 second time-frame it has no measurable AC Output. I checked pins 1 and 10 and had 24 ohms so I thought the brushes were OK. Thinking it was a controller, we bought one ( #327-1413) and it does the same thing.I don't have a frequency meter, and I don't really want a problem in the future burning up appliances or such.I have recently been noticing my output meter on my 16 volt battery charger " wagging"). I never noticed that before and actually bought a new charger as I thought this one was getting ready to crap out.The new charger doesn't wag, so I just thought it was indeed the charger.Maybe its just more forgiving...BUT, I'm wondering if its related. Ideas?

[schultz]

I have the same generator that had the exact same problem. A buddy of mine who works on Onans in the marine industry and has been to Onan training, told me this. Get a meter and check the Hz frequency at the outlet. It should be 63 Hz with no load 60 Hz with a load. If the generator goes up over 63 Hz it will shut itself off. I just had to adjust the throttle to get it into that range. Haven't had any trouble since. It's worth a try and won't cost anything.

Craig Schultz
S/ST 5909

[Bob Verwold]

Originally Posted by schultz

I have the same generator that had the exact same problem. A buddy of mine who works on Onans in the marine industry and has been to Onan training, told me this. Get a meter and check the Hz frequency at the outlet. It should be 63 Hz with no load 60 Hz with a load. If the generator goes up over 63 Hz it will shut itself off. I just had to adjust the throttle to get it into that range. Haven't had any trouble since. It's worth a try and won't cost anything.

Craig Schultz
S/ST 5909

That was my problem the whole time. An easy fix..............

[Jeff Niceswanger]

Thanks.....Will try this. Will let you know the verdict...Jeff

[erkme73]

Originally Posted by schultz

I have the same generator that had the exact same problem. A buddy of mine who works on Onans in the marine industry and has been to Onan training, told me this. Get a meter and check the Hz frequency at the outlet. It should be 63 Hz with no load 60 Hz with a load. If the generator goes up over 63 Hz it will shut itself off. I just had to adjust the throttle to get it into that range. Haven't had any trouble since. It's worth a try and won't cost anything.

Craig Schultz
S/ST 5909

Shultz, when yours shut down, did it generate a fault code?

[Rich Biebel]

Originally Posted by Jeff Niceswanger

Hi Rich,
A little info would be appreciated. We are just about to take our unit to the dealer but if there is something we could easily look at before we throw in the towel it would help. We have a 4000 Onan micro in a 2004 31 foot Four Winds( Serial #H020405714 Model 4KYFA26100K Spec K with 1500 Hrs.) and @ Columbus points race the starter drive busted in half. We dropped the unit out of motor home,ran to the Columbus Cummins dealer picked one up and changed it .Many busted pieces were throughout the shroud,so we took it all apart ,cleaned it all out, and re-installed everything. It took right off, and ran that whole day,but 24 hours later(next morning) it fails to start and sets a code 14(Over Frequency). It will run as long as you hold in the Start Button,and will run when its stone cold for about 30 seconds before it powers down. During this 30 second time-frame it has no measurable AC Output. I checked pins 1 and 10 and had 24 ohms so I thought the brushes were OK. Thinking it was a controller, we bought one ( #327-1413) and it does the same thing.I don't have a frequency meter, and I don't really want a problem in the future burning up appliances or such.I have recently been noticing my output meter on my 16 volt battery charger " wagging"). I never noticed that before and actually bought a new charger as I thought this one was getting ready to crap out.The new charger doesn't wag, so I just thought it was indeed the charger.Maybe its just more forgiving...BUT, I'm wondering if its related. Ideas?

Jeff you did a good job describing your problems and what you did to try and diagnose it was spot on. If you have a good Ohm reading across those 2 pins that is very important info. It confirms the brushes and the rotor are good. You tried a Controller and had no luck. When the starter drive broke.....not uncommon... a piece may have somehow gotten inside the rotor/stator area. If the stator was damaged......well that would explain why you have no AC output and a shutdown. First thing is to do as was suggested and try to read the HZ or frequency when it starts and you can hold the button down to try and help you get this reading. Unfortunately if it has NO AC outout you may or may not see a frequency that makes sense....They will shut down if they overspeed and the controller looks at the frequency since it is directly coupled to the engine. 3600 rpm = 60 HZ...62-62.5 is what it should be with no load applied....

I would be OHM testing the stator. Since you knew what the rotor Ohm readings should be.....you must have a Service Manual......If you do read how to test the stator windings.....You can do this right thru the plug in connector. May show you a problem.....May not....

The stator has the coils or windings that are wound inside the outer housing of the generator....Stator as in stationary.....Rotor as in rotating....

If the stator has an open or shorted coil....well that is your problem.

I have done just about everything you can think of on a 4KY...and changing a stator is not that unusual....

They can be very tough to diagnose.....and often are.....

[Jeff Niceswanger]

Thanks Rich
What has me puzzled is the fact it ran for one complete evening before it quit. But, you know machinery,its confusing .We are camping(wife/dogs are in a cabin,not the motor home) right now,with no internet service or phone. The main office of this place has Wi-fi, so I came up here a couple times now to check in with " the rest of the world". When we get back,I'll get back on this.., as this thing HAS to be fixed by Indy............'ll be in touch

[Jeff Niceswanger]

I am pretty sure I found it. One of the brushes was shot and not hitting the rotor all the way around .There was a spot about an inch long where it appeared to have not been hitting for a while. I took a scribe and pushed the brush up into the holder a little bit and it just stayed there,not returning. Rich, when I checked wires # 1 and 10 and got that 24 ohms, I made the mistake of not rotating the unit 360 degrees to be sure it was hitting everywhere. Amateurs mistake....I rechecked it, and it came and went severely. Onan in Columbus has the brushes and springs in stock, and We will pick them up and get this thing back together tomorrow, Thanks for all the help guys

[Rich Biebel]

Bad contact between the brushes and slip rings is one of the biggest things that can cause an issue like you have Jeff. If the brush does not contact the slip ring it will arc for a while and the arcing damages the surface of the copper......Clean it with some shop roll paper untill it is as clean as you can get it.

I have been working on a Miller 300 D Trailblazer-Diesel welder. Already have hours and hours in it, changed the rotor and PC control board.....and the board was already replaced once 6 months ago.....Weld output is intermittent at best.......I spent a good part of today trying to nail down the problem and find nothing that is clearly wrong.....but it doesn't work and I already have a pile of money in parts in it and a pile of time.....

Working with machines that produce electricity can be very very difficult....even for people that do it all the time like myself....

Hopefully you found your problem.....

[Jeff Niceswanger]

Well Well Well
Spoke too soon, I thought I had it fixed, but now it sets a different code, and still won't run without holding in start button. I now have hertz( 61 while holding button down)). I even have 14-20hz while the motor is being cranked, but I get a code 32. Low hertz while being cranked or something like that.Went ahead and PM'ed it while it was out. Plug, fuel filter, oil etc...I stuck it back in the back of the mini van and I going to take it to the dealer Monday. I checked everything I can think of, Stator/field ohms out (@35) perfect, brushes/rotor are 21 ohms. I have cleaned and tightened grounds and checked pins till I have had enough of it. I even stuck the old controller board back into be sure .. Same 32 code... I'll let you know what they find out.....