Most unreliable generator... EVER !!!

[zmotorsports]

Onan gensets for the most part are great performing gensets, but like others have stated they need to be excercised on a regular basis.

Without a code  or putting a meter on a couple of components we are  merely throwing guesses at you and not really helping diagnose much, probably just confusing you more than anything.  Going down the road and shutting down indicate a high probability of an electrical connection or issue.  Just out of curiosity how many hours do you have on it?  If you have many hours on it I have seen the brushed getting worn down and then the spring tension on them is at the minimum.  This allows some movement when hitting bumps and jarring the genset going down the road.

Have the Cummins/Onan dealership check the brushed just to be sure.  I like to stick a stiff piece of wire or a pick down into the brush holder against the backside of the brush.  I then take a Sharpie and make a mark at the point where it intersects the brush block.  Pull the pick out and if the measurement is anywhere near an inch indicating the brushes are recessed down inside the brush block 1" then they need to be replaced.

Also while they are there have them look at the slip rings for pits.  The slip rings should be smooth and shiny but they can have a black layer of carbon on them and be fine.  What you don't want to see is roughness or arc marks from the brushes bouncing on the slip rings.

If the controller senses a drop in voltage output for even a fraction of a second it will cut out the power supply to the fuel solenoid and shut it down immediately. 

Mike.

 

[WILDEBILL308]

Just to be sure this is a motion related problem, I ran the generator for 4 hours today with a very full load.

Performed flawlessly.

If it was a fuel pump issue, wouldn't it run badly whether moving or stationary? Is it safe to eliminate this as a cause?

Also, is it safe to assume oil issues do not come into play?

No you can't eliminate the fuel pump or connections because it ran setting in place just like before.
Have them check what zmotorsports posted and check the electrical connection on the fuel shut off solenoid. could be a bad solenoid.
Bill

 

[dpickard]

The hour meter is reading 735 hours.

 

[zmotorsports]

The hour meter is reading 735 hours.

That really isn't that many hours and the brushes should still be in good shape.  However, due to lack of use it could still be a slip ring issue or the brushes gummed up and stuck in the brush holder.  It would be worth at least mentioning to the service writer when you take it in.

If I was the mechanic working on it, I would have my meter hooked to the fuel solenoid feed circuit and then jar and bounce the genset as much as I could while watching to see if I was losing the voltage to the fuel solenoid.  IF that is the case then something in the control board is shutting down the fuel solenoid and not merely a fuel solenoid issue.

Mike.

 

[Gary RV_Wizard]

For comparison, I have 1900 hours on my Onan QD 7500 and it still works fine. Had a regulator go bad at around 1200 hours - a broken wire. Other than that it's just been routine oil & filter changes,

 

[NY_Dutch]

Just to be sure this is a motion related problem, I ran the generator for 4 hours today with a very full load.

Performed flawlessly.

If it was a fuel pump issue, wouldn't it run badly whether moving or stationary? Is it safe to eliminate this as a cause?

Also, is it safe to assume oil issues do not come into play?

No, it's not safe to assume oil issues do not come into play. A faulty oil level switch my work fine when stationary, but fail when in motion as the oil moves around from the vehicle motion. The oil level being low may also only show up as the vehicle tilts and vibrates. That's easy enough to check though...

 

[Chuck and Lori]

We have an '07 Bus too and I don't see where anyone mentioned the extra fuel filter that Tiffin adds to the generator.  Are you aware of this one?  It's an inline filter and the best way to explain where it is located is under the driver's foot on the fuel line to the generator.  There have been lots of folks on the Tiffin forum that had issues until they changed this filter.  Maybe it's not your problem but it's easy to replace and can't hurt to put a new filter in place. 

Thanks  Chuck

 

[blw2]

i find these onans interesting
Mine has stumbled and shut off a few times now.
but generally fairly reliable and starts right back up so far.

They replaced the pump when I bought the coach new since it wouldn't start in by PDI.... presumably form sitting on the dealer's lot.

This whole running thing to keep them operational.... I find myself running the thing more as a maintenance thing than for really needing it.  That I struggle with conceptually.  Running 45 minutes or an hour or whatever per month is a lot!  They do seem nearly bullet proof, BUT having to run them that much clearly they are not.... and with so many threads about problems tells me they can be very finicky.... so are they really bullet proof?

I guess I'd feel better about it if it were quieter....

 

[Gary RV_Wizard]

There are two reasons for exercising a genset. Gas gensets have a carburetor that is very susceptible to contamination from the residual oils in fuel that evaporates when it sits for very long. Running the genset regularly keeps fresh fuel cycling through the carburetor and avoids that problem. This is not an issue with diesel gensets that have no carburetor and use a fuel that doesn't evaporate as easily

All gensets, however, have major electrical components that are susceptible to accumulated moisture (humidity & condensation). Running the genset for an extended period heats up the entire genset enough to drive out any moisture. If the RV is in the high desert, this may not be much concern, but in most of the country the humidity plus temperature changes are likely to cause moisture build-up in the various windings of the generating components and on the circuit boards that now control everything.

 

[blw2]

here's a sidetrack question.... to those of you that have the little high end honda generators
aside from the old fuel gumming up the carb, do you have to run your generators monthly for them to remain reliable?

 

[SargeW]

I believe when I had my Honda 2000 the recommendation was that if it was going to be sitting for a while not used, to turn off the fuel valve and run it until it stalled.

 

[zmotorsports]

I believe when I had my Honda 2000 the recommendation was that if it was going to be sitting for a while not used, to turn off the fuel valve and run it until it stalled.

That is a good recommendation on all of them nowadays, not just a Honda.  The ethanol added to the fuels today are what wreak havoc on these small engine's fuel systems.

Mike.

 

[Gottasmilealot]

I'm thinking it's a short or bad connection that occurs just when moving, as it runs fine otherwise. I had a vehicle that would quit just like you say.  It turned out to be a wire that had its insulation rubbed off next to the frame.  With movement, the wire would short against the frame and short out. 

Try tracing all wiring for worn insulation or damage where it might run near the frame or run through a rubber grommet at metal work.  Also, look for a corroded grounding strap or other bad electrical connection in the system.  It's probably a ten dollar repair that will take hundreds of dollars to find.

I feel for you.  Been there.

 

[dpickard]

Hey Chuck and thanks for mentioning this. I dont recall seeing a charge for an inline fuel filter on the bill. It just says "fuel filter."

You wouldnt happen to know the part number would you? I thought maybe if I had that I could compare it to the parts list by number to see if it was changed.

Dianne

 

[dpickard]

The seller (dealer) and the former owner (whom I have spoken to on several occasions to ask questions about the coach) BOTH swore to me that the generator had never had ANY problems before I bought it and that whatever was wrong with it NOW was NOT wrong with it when I took ownership.

Today I was deep cleaning the interior of the coach and I found not one, but TWO receipts from the Cummins Atlantic shop in Greensboro laying back against the wall under one of the sofas.

Apparently this problem has been going on for at least a full YEAR!

Receipt #1
Date: October 2, 2014
Cause: Short in harness from generator to inside dash switch
Replaced Start/Stop dash switch

Receipt #2
Date: January 19, 2015
Cause: Shuts down unexpectedly. Hard start. Fault code: 36.
Troubleshoot Fault code 36
Attempted to start. Would not start without coach running. Unit started and ran ok with load. Unit makes 120.2 volts AC at 60Hz. No load.
Unit load tested ok. Shut unit off and restarted. It started and ran ok again.

Kinda seems like I have not been told the truth, huh?

I just don't know WHERE to go or WHO to turn to next. I have never seen a generator with such gremlins. I thought I had it isolated to a movement issue. Now, it will run for about 9 minutes and shut down while sitting still.

This is one for the books.

 

[driftless shifter]

Send copies of receipts with the message you lied to me, what do you intend to do to fix this issue. PS; next communication will be from an attorney if this is not worked out. That ought to bunch up some shorts.

Bill

 

[SargeW]

Wow, someone lied to sell a RV? Say it ain't so.........

 

[Lou Schneider]

The single cylinder Hondas should be run dry before being put into storage.  If there is no fuel in the tank or carb, there's nothing to gum it up.

Another step that you can do with a single cylinder engine but not with multiple cylinders is to seal the combustion chamber from the outside air.

Just pull on the starter rope until you feel resistance, this puts the piston at the start of the compression stroke with both valves closed.  Honda recommends doing this before putting the generator in storage.

Multi cylinder engines always have at least one cylinder open to the sir no matter where they stop.

So, no ...there's no reason go exercise a small generator once its set up for storage.

 

[John From Detroit]

You were indeed told the truth.

Problem one was with the remote control harness... Not the generator

Problem 2 is dead house battery or bad connection.. Again not a problem with the generator which tested and worked perfectly once started.

So in truth the generator has not been a problem.. The problems were all external to the generator.

And yes, I agree with you.. Though the salesman did not exactly lie.. He also did not tell the truth.

Two other things:

1: Generator needs monthly exercise.. Mine was done on the laSt day of the month this time instead of the 1st due to issues with shore power.. (Hey what's one day, some moths have more or less days)

2: In parts of the country (Michigan for example) if you purchaSe gasoline in the summer for a NON FUEL INJECTED engine (Most generators still use carbs) the engine may not start in january.. I do not know the switch over date but Winter gas works year round, Summer gas does not.. HOW TO FIX:  Pre-heat carb (Light bulb nearby) Get it up over aay 60 or 70 degrees,, Then it works.

Yes, I know why  (Google Boutique gas, if you want an explanation)

 

[dpickard]

My generator is an Onan Quiet Diesel 7500.