Onan 4000

The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.

dktool

Well-known member
Joined
Apr 3, 2015
Posts
163
I also did complete the insulation and exhaust quieting project on this.
Started with an obvious thing, putting rubber cushioning washer between the bottom pan and the mounting rails on the 4 bolts.
Then I lined the enclosure (sides, back and top) with 1" egg crate type sound dampening foam.
I also used some 80 mil Kilmat (comparable to Dynamat for less $) to cover the outside of the cooling fan cover and various sheet metal areas on the exterior of the enclosure.

For the exhaust I was concerned about potential increased back pressure by extending the exhaust to move the exit toward the front of the coach.
I teed a vacuum gauge into the source for the choke pull off to get a reading as it was originally, then went on to experiment with what became an overall net increase of 5-1/2'
There was no noticeable increase in back pressure on the gauge.
These engines are such low spinning, small breathing units that I wasn't expecting the increased length to cause an issue.
I used the original 1.5" o.d. 90 degree pipe the was connected to the muffler as the exit piece, moved forward with a 5.5' length of 1.5" o.d. flex exhaust tubing.

Overall the improvement in engine and exhaust noise is HUGE.
 

Attachments

  • 20220214_104408.jpg
    20220214_104408.jpg
    148.7 KB · Views: 10
  • 20220214_103821.jpg
    20220214_103821.jpg
    155.8 KB · Views: 11
  • 20220214_103609.jpg
    20220214_103609.jpg
    105.5 KB · Views: 10
Last edited:

dktool

Well-known member
Joined
Apr 3, 2015
Posts
163
The final chapter in my generator mod has now been written.
After a couple months of having the catalytic converter quest bouncing around in my head I finally found one small enough to persue.
Being that I live in Commiefornia I couldn't buy it from normal sources as it didn't have the CARB stamp of approval, but a guy on Ebay came through.
A couple of mods on the inlet and outlet and 2 clamps and done.
In a perfect world it would be located before the muffler but it's close enough to the heat source that the cat starts cooking quickly.
Really cleans up the stink.

20220327_164847.jpg20220328_095032.jpg
 

udidwht

Well-known member
Joined
Jun 3, 2018
Posts
104
Location
Renton, WA.
I'm back with another question...

Does anyone know what the static main jet adjusting screw setting should be on this carb ?
My plastic "altitude reference" cap is missing and the manual gives no information on a x-many turns from all the way in for a starting point.
According to the manual 2 turns from lightly seated (altitude knob). Pages 8-9 thru 8-14


Buy yourself a 'Kill O Watt' meter' The issue when the generator runs while holding start switch down only is almost always the...

Voltage regulator or oil pressure switch

Kill o watt...https://www.amazon.com/P3-P4400-Electricity-Usage-Monitor/dp/B00009MDBU
 
Last edited:

dktool

Well-known member
Joined
Apr 3, 2015
Posts
163
According to the manual 2 turns from lightly seated (altitude knob). Pages 8-9 thru 8-14


Buy yourself a 'Kill O Watt' meter' The issue when the generator runs while holding start switch down only is almost always the...

Voltage regulator or oil pressure switch

Kill o watt...https://www.amazon.com/P3-P4400-Electricity-Usage-Monitor/dp/B00009MDBU
See post #35

Also, I installed this;
MICTUNING AC LCD Display Digital... https://www.amazon.com/dp/B07ZHDMZJ8?ref=ppx_pop_mob_ap_share
 
Last edited:

udidwht

Well-known member
Joined
Jun 3, 2018
Posts
104
Location
Renton, WA.
The meter comes in handy (as does the Kill O Watt). This also comes in very handy...
 

Attachments

  • 20220427_144846[1].jpg
    20220427_144846[1].jpg
    172.9 KB · Views: 9

DonTom

Well-known member
Joined
Apr 21, 2005
Posts
7,113
Location
Auburn, CA or Reno, NV
That is the single biggest hurdle folks have with these Onan generators...diagnosing
What type of stuff does it test for?

My gennys have the diagnostic light and trouble codes. That plus a frequency and voltmeter has worked well enough for me. But I cannot get more than around 1.5KW max out of it at 7K' elevation. Far from the 4KW capacity. And even for that, I had to reduce the genny RPMs for 55 hz or else it kept on dying. Don't have these issues at 1,400' (in Auburn, CA). I didn't test it here in Reno (5K' right here). It now works fine for higher loads and at 60 hz.

-Don- Reno, NV
 

udidwht

Well-known member
Joined
Jun 3, 2018
Posts
104
Location
Renton, WA.
What type of stuff does it test for?

My gennys have the diagnostic light and trouble codes. That plus a frequency and voltmeter has worked well enough for me. But I cannot get more than around 1.5KW max out of it at 7K' elevation. Far from the 4KW capacity. And even for that, I had to reduce the genny RPMs for 55 hz or else it kept on dying. Don't have these issues at 1,400' (in Auburn, CA). I didn't test it here in Reno (5K' right here). It now works fine for higher loads and at 60 hz.

-Don- Reno, NV
It will test all the 'electrical components' in the generator. It will even allow the generator to run if one is not functioning properly (or at all). It won't allow a faulty fuel pump to pump but eliminating that as a first step is easy. Greatly eliminates one throwing parts at an issue.
 

Latest posts

Forum statistics

Threads
123,976
Posts
1,258,602
Members
129,815
Latest member
Rideaway
Top Bottom