wa8yxm
Davison Michigan (East of Flint)
Senior Member
Joined: 07/04/2006
View Profile
 Offline
|
My ONAN had an altitude adjustment on, I think, the side of the Carb or near the carb... You may need to increase it Per page 11 of my owner's manual not all ONAN's have them.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times
|
JoeH
Apollo Beach,FL
Senior Member
Joined: 02/21/2001
View Profile
Good Sam RV Club Member
Offline
|
wa8yxm wrote:My ONAN had an altitude adjustment on, I think, the side of the Carb or near the carb... You may need to increase it Per page 11 of my owner's manual not all ONAN's have them.
My old Onan had an altitude adjustment lever on it too
Joe
2013 Dutch Star 4338- all electric
Toad is 2015 F-150 with bikes,kayaks and Harley aboard
|
garyemunson
Reno, Nevada
Senior Member
Joined: 09/27/2015
View Profile
Good Sam RV Club Member
Offline
|
You can pry the little black limiter cap off the altitude adjuster to allow you to open the adjustment a little further. That will probably temporarily fix your issue. The jet that the altitude adjuster varies the size of is likely partially clogged. That (main jet) jet is right at the bottom of the float bowl and if any gas is left in the carb during storage, that is where the deposit builds up as it evaporates. Will cause low-power lean running that will stall the genny if a significant load is put on it. If that strategy gets it working OK again, plan on cleaning the carb jets once you are done using the RV. Onan discourages cleaning the carbs to sell new ones. Really are not too many "mechanics" capable of doing that anymore anyway. They are good, reliable carburetors that generally just have "dirty jet" issues. The main jet at the bottom of the float bowl is the most important and most often overlooked. Tricky to clean as the fuel supply enters it sideways from the altitude adjuster screw. A good overnight soak of the metal parts in lacquer thinner and "rodding out" of the passages with a broom straw (DO NOT use anything metal or you WILL be buying a new carb!!) will do the trick.
|
valhalla360
No paticular place.
Senior Member
Joined: 08/19/2009
View Profile
Good Sam RV Club Member
|
Did the Onan certified tech do the adjustment correctly?
Assuming we are talking about a single air/con unit on a 4000w generator, it should be OK even at altitude. My best guess is the tech didn't do the adjustment correctly.
One simple trick you can try is to turn on the fan mode, let it settle in for a minute, then flip it over to the air/con mode. This way you don't have both the fan motor and compressor motor surging at the same time...but this only works if you are borderline. If the microwave by itself is causing it to choke, it's probably not just close.
Tammy & Mike
Ford F250 V10
2021 Gray Wolf
Gemini Catamaran 34'
Full Time spliting time between boat and RV
|
rwynkoop
St. Louis MO
Full Member
Joined: 10/04/2005
View Profile
Offline
|
I can second the easy start option. My 13,000 BTU AC can now be started with my 3000 watt generator when in ECO mode. In the past I had to run in normal mode.
If your generator is having problem handling the load, easy start may be the way to go. Even though it is expensive it works well.
MicroAir Easy Start - for about $330.00
Also, check this video of someone who also had a problem with their generator shutting down, even after a few ONAN techs worked on it.
Nomadic Fanatic - Fixed my generator - YouTube.
Robert Wynkoop
2003 Chevy 1500 HD Crew 4x4, 6.0L gas.
2007 Jayco 29BHS TT.
|
|
|
Grit dog
Black Diamond, WA
Senior Member
Joined: 05/06/2013
View Profile
Offline
|
Look into leaning it out more. Dunno what model yo have, but some (all?) have an altitude adjustment screw.
However, it would have to be running VERY poorly, very rich to not have enough snort to at least run the microwave, even if it's a little 2500W unit.
Check spark plug. If it's fouled and or dark/black then it's running rich. Insulator ideally should be a cardboard brown color. White = lean, black = rich.
Air cleaner presumably is clean since you just had it serviced, but running no air cleaner could help diagnose, it might get a "little" more air, not significant though.
Fuel, if it's fresh shouldn't matter. Octane requirement goes down as altitude goes up. Guessing it's gasoline though since you didn't specify, but you said it's in a moho.
Possible carb plugged?
And if it's LP? I'm not familiar, but presume they have an alt adj as well?
2016 Ram 2500, MotorOps.ca EFIlive tuned, 5” turbo back, 6" lift on 37s
2017 Heartland Torque T29 - Sold.
Couple of Arctic Fox TCs - Sold
|
mr_andyj
Georgia
Senior Member
Joined: 11/13/2004
View Profile
|
4,000 watts times 0.775 is 3,100 watts at 7500 feet elevation.
RV Roof Top Air Conditioners Watts Required for start u____Average wattage once running
7000 btu RV air conditioner 1700 ________________________600
10,000 btu RV air conditioner 2000________________________700
13,500 btu RV air conditioner 2750_______________________ 1250
15,000 btu RV air conditioner 3500_______________________ 1500
from https://www.ramsond.com/wattage-chart/
So, if you have a 15,000 BTU AC then at 3100 watts you are 400 watts shy.
If you have 13.5 then you should have plenty if running ONLY the AC.
10 and 7 btu no problem. You obviously dont have these.
This chart assumes an average inefficient RV AC unit like dometic or coleman or similar.
I suspect a carb issue and that your motor, as a result, is not able to run at peak power.
My gen runs at about 42-50% capacity when AC is running (if at 7500 feet). Yours is needing most of its capacity to just keep the AC going.
* This post was
edited 06/24/21 05:51pm by mr_andyj *
|
3 tons
NV.
Senior Member
Joined: 03/13/2009
View Profile
Offline
|
Per the law of Occam’s Razor I would punt for a properly sized generator - per your situation, this is the right tool from your toolbox…
3 tons
|
TurnThePage
North ID
Senior Member
Joined: 10/08/2003
View Profile
Offline
|
If your built in generator is genuinely running properly, I would try the following in order:
1. MicroAir Easy Start (or at least a hard start capacitor)
2. Shut off all other loads including the converter
3. Purchase a larger gen for high altitude trips (There's lots of good deals for Chinese ones out there.)
2015 Ram 1500
2022 Grand Design Imagine XLS 22RBE
|
SFVdave
Southern California
Senior Member
Joined: 05/18/2007
View Profile
Good Sam RV Club Member
|
Looking at option of removing the altitude dial which limits turning and to 5000 feet. If I can turn it a bit more may do the trick. I know it's not recommended.
|
|
|
