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Saturday, April 3, 2010

Three R’s - Removing, Rebuilding and Replacing our Onan 6.3KW LP Generator

Well, we were having trouble with our generator last year and kinda ignored it …   but now this Spring, dear Steveio wanted it fixed and working.   We have a little time before camping season begins.

The great guys at Flight Systems were VERY helpful with troubleshooting.   Randy was “The Guy” to talk to about the system.
Their diagnostic troubleshooting information is the best and we sure appreciated their help.   They have downloads of information and what things to test first, second, third etc. and using a voltmeter, you can diagnose what is wrong with your own generator before paying for costly repairs.

So after checking it all out, we found a shorted brown burnt spot in the control board, and a bubbled area on the voltage regulator.  We think that our old batteries with the bad cells and the exploding expanded case on two of them ruined our generator somehow with a back surge of something or other.  (we have all new batteries now)
We threw a new control board at it, then a new voltage regulator, then cleaning the slip rings, and replacing the brushes (plus the ceramic holder cracked so had to replace that too)  … finally we came to the conclusion that it was only putting out 55 volts and not 120vac.   That meant the half of windings on the rotor were bad.  Sigh. 
So that meant a removal of the generator, and take off the rotor and send it in to be completely rebuilt.  We found a great guy down in Ohio,  name of :
SAM BORCK - 11392 CTY RD 5 - DELTA, OH  43515 -   419- 466-0485
He seemed to know the generators inside and out, exactly the specific stuff about our model and year and did very prompt turnaround, we got it back within a week of him getting it!  Cost was $365 including his shipping it back to us.  What a deal compared to what Onan wanted for a new one, or what even other places on the net wanted for a rebuilt one.

I was the Gopher Girl and Steve patiently stopped from time to time to let me take pics of each step.
Here are the pics of removing it last month while we still had snow.


(p.s.  in case you are wondering, that funny yellow adaptor and orange cord hanging off the side of the rig is our AC  line from the garage 20amp outlet for shore power.  This adaptor is a screw on type bayonet mount for 50amp plugs.  Instead of keeping our heavy black 50amp cord out there all the time, temping for copper thieves, we use this adaptor and a regular extension cord, sufficient for light enough loads while parked in our driveway)

Okay.. back to the generator---    Now it’s a couple weeks later and we got the rotor rebuilt and back.. and the snow is gone!  


All those pics were taken yesterday evening …  now it’s Saturday morning and Steve finished up the connections. We attached the propane line, bled it, checked for leaks… double checked all our connections…. and hit the button!
annnndd it WORKS!!!!! 
wheeeeeeeee  120 vac at the outlets… yahhhhoooooooooo

Generator Muffler Replacement:
On day five years ago, when Steve went to start up the generator for a little exercise (plus he wanted to run our vacuum cleaner to do the lower compartment carpeting)   it started up with big roar and a backfire BANG!    What was up with that?  The dogs almost went through the roof!

We shut it down immediately and went out to investigate.  Yikes!  It blew the back off the rusty muffler-----   time for a replacement!   Plus, Steve looked at the throttle linkage again which needed more lubricant.  It had hung up once in January and he lubed it then, but it was still a little sticky.  That is probably what caused the backfire.

Steve called around to various places to see about getting a new muffler, and explored the internet to see if he could find one cheaper.  Amazingly, the cheapest place he found, was right from the Onan / Cummins place in DePere, WI (just south of Green Bay)

 $77.76 with tax
part number 542-0472  RV exhaust kit Emerald LP Generator
It was a muffler, a hanger bracket, a manifold connector, and 2 clamps and bolts and a gasket

First step was to take off the old manifold connector.  Of course, it was rusty and the bolts broke off when trying to remove them.  Steve was working flat on his back on the ground with the manifold opening being up over his head.  ARGGGHHHH

He had to drill out the broken off bolts....  Once he got it off, he used a tap and re-tapped the threads of the two holes.  These photos are from looking up from underneath the rig.  When he attached the new manifold adapter and gasket, he felt the two bolts just screwed into the new threads might not be enough.  There is a lot of vibration on a generator---   (flashback to last summer when oil was pouring out of ours... seems the filter had vibrated loose and oil was leaking out all over)   

In this case, Steve decided to use longer bolts, lock washers and locking nuts on the top end of the bolts where his fingers could barely get up on the top side of the flange.  But now it is more secure and won't rattle loose (we hope) 

This is looking up from the ground to where he attached the manifold adaptor

Next comes the muffler itself.  It came with a hanging bracket and muffler clamps.  Don't you just LOVE new metal pretty shiny parts????

We set it up into place, clamped on the hanging bracket to where the old one was attached and then added the muffler clamp around the manifold adapter.  It was a really snug fit and we are sure it's nice and tight.   Last step yet to go, he has to attach a tail pipe.  (a section of conduit piping will work just fine)  but he has to go buy it today as he was not sure of the length and diameter needed until I brought home the muffler.

Once it was all in place, we started up the generator, with no backfires and no stuck linkage.  Wheeeeee!!!!     It was very quiet again.

Generator Oil Change:
Every year we take care of our generator with an oil and filter change.   We do it every spring, even though we have only put on about 61 hours since last spring when it was done.  The little hour gauge inside helps keep track of the time in between changes.

Here is how we do it:

First, we warm up the oil by running it for a while.  Then we shut it down and set a bucket underneath by the drain.  We write it on the filter with a permanent marker at what hours of usage we are at each time we change it.

Steve unscrewed the petcock to let the old oil drain out into the bucket...   It starts running out, but also carefully opening the top fill cap lets it run out even faster.  We are careful to not let anything get into the opening, so we replace the cap quickly as soon as the stream into the bucket slows down.

 Looks pretty good... 

and once it's all out, time to unscrew the filter.  
Notice Steve's wonderful filter wrench?? LOL

It's the same "secret special tool" that is used to remove injectors
after sitting 4 days on a corner in Winslow, Arizona---- 
for more information--- see the blog at:

Added the new oil --- here are the specs and part numbers:

 filter number WIX 51762
or 122--0800 ONAN

Oil change all done, and ready to run again....


  1. The Master at work, you can be glad Stevio has the expertise to do these jobs as genorators are big money holes. Now Sam is getting the bug to dewinterize and get the 5th wheel ready for its great adventure. just the thought of getting it detup for full time is intimedating. Good work Stevio.Sam&Donna.

  2. Always boggles my mind how people are so gol darned smart at doing all this kind of stuff. It seems most guys I know are all do-it-yourselfers. And they are all good at everything too. You are soooooooo fortunate to have such a super handy guy. I am fortunate to have a super duper handy gal...... AL:))

  3. Ha.. we fix it and learn how by necessity. Can't afford to pay someone else to do it! LOL

  4. Good job! I wish you had have been closer. We have a great hydrolic list table that would have lifted that generator right up for you. We used it when we moved for our big old fashioned tube type tv.

    Your motorhome looks so shiny! What do you use on it?

  5. Forgot to tell you. The link for the fight systems didn't work.

  6. Oh thanks for letting me know about the link... I fixed it now.

  7. What an incredibly talanted guy!

    You married well! ;c)


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