Onan Microquiet 4000

Hello, 1st post but have read & searched through so much over the last couple years. Will probably say more than necessary but sometimes more info helps. This generator not installed in rv, yet. Bought out of another rv & ended up installing a new carb. Ran the carb a few times & let it run out of fuel. It did sit for a couple months though. Had it outside for awhile & a very industrious mouse set up home in the coil area (if something doesn't move for a day or two it gets occupied by these pests & they pack things quickly...these rural farm mice are very industrious) It was a chore getting everything cleaned out! Not sure if might have disrupted things while cleaning. Do know the choke spring became dislodged but think put it back right. Thought it would go into one of the holes but seems to just connect to the arm that bends down per some pics posted elsewhere on this site (excuse my lack of proper terminology). I'm someone that can usually repair mechanical things but sometimes get myself into trouble & folks like you have always helped me figure things out. The electrical stuff is where I am more wary to venture unassisted.

Wired an outlet to the generator & have plugged in a compressor & heater. The heater is 1500w. The compressor 13.8 amps. If the compressor shuts off the generator shuts down with overvoltage code 14. If generator & heater running all goes well & have run it for 3 days of 2 hrs each until gas ran out or shut it off. If I try to plug in & turn on a hairdryer 1875w in addition to the other two it will shut the generator down. Does this sound like proper running?

Reason ask is the friend that wired the electrical outlet fiddled with the throttle stop screw. The generator previously ran & has a black mark on the butterfly where it usually contacted the choke lever?. These marks were on carb from factory & that is where it ran before. Now it runs with much more of the butterfly forward of the lever.

I want to make sure this thing is running as it should before installing it. Also, have been running 100% gas plus seafoam thru it. It seems to like the seafoam addition and doesn't start without manual assistance pushing the butterfly with just the gas. With the seafoam it will start & continue to run 1st try as long as get load put on it right away by turning on heater then compressor. But if no load quickly it shuts down. Could I have a bit of varnish that needs to yet be cleared out?

Onan Microquiet 4000 4KY FA26100J spec J, S#G010263059

Have manuals & trouble shooting guides but not sure if have a problem or not. ideas & any input appreciated.

j-d
Explorer II
May 19, 2016
There are a few carb/choke linkage pix on this site. I have some on flickR that I'll try to find later.
I think the "idle" passage(s?) in that carb may be gummed up. It doesn't take long and running out of gas doesn't dry the whole carb out. I put "idle" in quotes because even though it's a 3600-RPM unit, it needs idle passages to run with little or no load.
Let me know if you need the pic.
N-Trouble
Explorer
May 19, 2016
"Microquiet" what a joke of a name. Wonder who the genius in their marketing dept that came up with that.

Sorry, everytime I see that name I cant help myself.
road-runner
Explorer III
May 19, 2016
N-Trouble wrote:
"Microquiet" what a joke of a name. Wonder who the genius in their marketing dept that came up with that.

Sorry, everytime I see that name I cant help myself.

X2!
alwaysfixinsome
Explorer
May 19, 2016
Thanks for the input. Was wondering if there might be some buildup but it does seem to be slowly getting better running lots of seafoam. Just wanted to make sure I'm focusing on the right problem & that it isn't something else. I read somewhere on here that some have recommended running some racing fuel thru it to clean it out & just keep at it. I can get some next time in town. At least it runs, so fuel+additives go thru it allowing something to hopefully clean it out. Really don't want to be investing in another carb unless absolutely necessary.

I found helpful pics that CloudDriver posted Oct 2011 on this very site. If you have some others that might help they would be appreciated

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/25457462/srt/pa/pging/1/page/1.cfm

Your input so far seems to be pointing me to carb being the issue or at least main issue.
j-d
Explorer II
May 20, 2016
Linkage Photo

Using screwdriver on inverted air filter element wing nut to pry blower housing away from carb's butterflies

There are better cleaners than SeaFoam, Berryman being one. I've heard of taking the fuel line TO the carb off and filling with Berryman. It'll start because there's still gas in the carb. Run a few mins then let stand. Repeat. You're trying to let the Berryman soak the Idle Passages.
alwaysfixinsome
Explorer
May 22, 2016
Thanks for tip on Berryman. Will be doing that. Hope solves the problem.
pnichols
Explorer II
May 23, 2016
N-Trouble wrote:
"Microquiet" what a joke of a name. Wonder who the genius in their marketing dept that came up with that.

Hmmmmmm .... I wonder what other 4000 watt constant-speed generators out in the open in just the cabinet they come in have a noise level of around only 60 dB(A) @ 50 ft (National Park Standards) at one-half power?

The (current) Onan 4000 does this. I believe that the 11 year old model in our Class C motorhome even has a spec of only 66 dB(A). Of course certain variable-speed (inverter) generators, such as the 3000 watt Honda EU3000iS are quieter - but they may not be of the right size, power, and weight for small motorhomes - as the Onan 4000 is.

How quiet and vibration-free they are when mounted in RV's is up to the builder of the RV. They have to be mounted on high quality isolation mounts and they have to be mounted in cabinets closed on all sides except for the bottom - with none of the green Onan case visible hanging out the cabinet openng at the bottom.

The Onan 4000 decently installed by Winnebago in our small motorhome is fairly quiet and vibration-free ... considering it provides 4000 watts constantly on tap at all outside temperatures ... including extreme desert heat in the summer. There is very little vibration in our coach floor. We sometimes nap in the middle of a hot day while our Onan 4000 is powering the A/C. We have left it running the A/C almost throughout the entire night in the Southern U.S. in August so that we could sleep in the extreme heat and humidity.

I feel that the Onan 4000 sometimes gets a bad rap through less than optimum installations by some RV manufacturers.

However, a similar physical size and weight 4000 watt variable-speed inverter generator designed for permanent RV installations would certainly be a welcome appliance in new rigs if it was as reliable as the Onan and priced not more than say, $500-$800, above the price of the ~$3K Onan 4000.
N-Trouble
Explorer
May 23, 2016
Completly agree. If a more modern variable speed that is drop-in compatible were available Id buy it in a heartbeat.

As for install of the current rattle can I will try to go hear what a quiet/vibration free one sounds like. Have any links to good mounts? Exhaust seems fairly quiet. Most of the noise to me is coming from the fan. That area also has to be open which is right on the front of a 5er. Front queen sits right on top of the genny and is nearly impossible to sleep when running.
pnichols
Explorer II
May 23, 2016
The sleepiing areas in our Class C are away from where the Onan is mounted in it's exterior cabinet. The coach area above where our Onan is mounted was heavily carpeted by Winnebago, probably not intentionally by them - but resulting in further sound deadening and vibration isolation. Most of our Onan's outside noise is the air flow sound from it's substantial cooling system designed by Onan so as to provide up to a full 4000 watts always reliabily available even in high ambient temperatures.

I have done a couple things that MAY be helping with our Onan's relative non-labored sound and smoothness: I use Mobil 1 oil in it and an E3 spark plug in it.

Here's a couple of links for isolation mounts superior to the usual stock simple hard rubber ones used by Onan 4000 generator installers. (Note that when choosing Onan isolation mounts, you have to select ones that are rated to meet both the vertical and horizontal G-loads as specified in the Onan installation documents.):

http://www.avproductsinc.com/index.html

http://www.caldyn.com/content/home.html
Sez_Hoo_
Explorer
May 23, 2016
There is an adjustment on the carb for elevation. Not sure if this is an issue for you but it was for my friends Onan.