Onan genset, old tech, too loud.

Honda made RV built in generators for a while. They were a technological step up from Onan's, as they were water cooled (a big deal, that does alot to quiet the motors), but not inverter based..

I don't see anyone coming up with a fuel injector generator for our use unless it becomes mandated. It would be a lot of expense with next to zero gain.

Park next to me, My Champion will make yours quiet.

Snowman, my first two RV's were B's with underhung 2800 Microlite Onans. I suppose your 4000 is a Microquiet, but I dunno the details of how it's mounted.

On mine, the first thing was the exhaust. Be sure the tailpipe is free to move, not rigidly attached to anything (this lets the anti-vibration mounts in the box work). I made a spring hanger to replace a rigid one. Install the Onan resonator. It won't make a huge difference in noise level, but will lower and smooth the tone so it's less irritating to most folks. Rodger (old B forum mod) also bought a small Supertrapp spark arrestor to use on the end of the pipe when parked.

If the Onan is mounted by being hung on end plates, use longer bolts, Loctite, and rubber washers to reduce the metal-to-metal contact. Loctite keeps you from having to tighten the bolts beyond just 'snug', so the rubber can flex. If your mount uses a 'V' brace on the side opposite the service door, be sure it's not rubbing on the box's upper lip (was on one of mine).

Read the installation manual and do some measuring and thinking. You may have room for some sound deadening above the box, on the bottom of the floor. It's unlikely to be worth all the effort, but you may be able to fabricate a metal baffle that wraps around the air inlet area, and line it with sound-absorbing material like underhood Dynamat. The manual gives needed clearances.

Finally, the worst source of noise is the downward cooling air exit around the exhaust pipe. If yours is high enough off the ground for it not to present a fire hazard, put a square of old carpet under the generator when parked. It'll absorb some noise before it bounces off the pavement.

Jim, "Vote early, and vote often!"

I've grumbled about the old techness of generators on this forum for years with very little agreement from anyone. Mid 1970s carburetor design, prone to clogging from periods of disuse. Noise, stinky exhaust.

I have the 4K Onan on my class C. I agree noisy and dated in general. I've written to Onan requesting a new model.

All I can say is until more than a small handful of RV'ers complain about these dinosaurs, they will continue to be installed.

copeland343 wrote:
I feel good about our 4kw Onan 1800 rpm twin cylinder generator. All we hear is the cooling fan. When a 3600 rpm single cylinder generator shows up cant be heard. Sometimes old is good.

X2

Handbasket wrote:

mlts22 wrote:
....

It is all in the installation. Shock mounts, acoustic insulation, exhaust resonators, suspending wires and pipes to help damp vibrations, suspending the exhaust pipe with rubber mountings so it doesn't rattle, and making sure there is easy access to the front panel for oil changes and checking the generator breakers.
....

X2,+. Most RV makers do the cheapest & easiest install they can. Then owners sit around and gripe about the noise instead of getting the installation manual and seeing what improvements they can make.

It takes some thought, effort, and a few bucks but an installed Onan does not have to make a major racket. First check the installation manual for needed clearances and openings. Then be sure the exhaust is free to shake, and add the resonator; insulate the compartment and the door; put some rubber between the generator base pan and RV's frame.

Probably the biggest bang-for-buck reduction I made in my 2800's noise was when I found out from the manual that the Tiger had _FAR_ more than the required minimum cooling inlet opening. Bought some foil-faced rigid fiberglass insulation, and insulated the inside of the door. Reduced the inlet opening by 2/3's (still almost twice what Onan requires).

Since then, I've installed insulation on all sides of the compartment (quieter inside and out), added rubber sheet washers under the mounting points, and made other improvements.

Yeah, Onan could and should do better. But so could the RV maker; it's not all Onan's fault.

Jim, "Some days the best thing about my job is that the chair spins."

My Onan doesn't sit in a compartment. It hangs beneath the frame of the MH, albeit behind the sidewall which simply hangs down. You can see the bottom of the genset below the wall. So, is it a lost cause as far as noise abatement?

pkunk wrote:
I've had many comments on how quiet my 5500 Onan is. 1800 rpm and gets slightly louder under full load but it's a low frequency sound that can hardly be heard on the curb side.

Same here...our 5500 is very quiet, inside and out...

mlts22 wrote:
....

It is all in the installation. Shock mounts, acoustic insulation, exhaust resonators, suspending wires and pipes to help damp vibrations, suspending the exhaust pipe with rubber mountings so it doesn't rattle, and making sure there is easy access to the front panel for oil changes and checking the generator breakers.
....

X2,+. Most RV makers do the cheapest & easiest install they can. Then owners sit around and gripe about the noise instead of getting the installation manual and seeing what improvements they can make.

It takes some thought, effort, and a few bucks but an installed Onan does not have to make a major racket. First check the installation manual for needed clearances and openings. Then be sure the exhaust is free to shake, and add the resonator; insulate the compartment and the door; put some rubber between the generator base pan and RV's frame.

Probably the biggest bang-for-buck reduction I made in my 2800's noise was when I found out from the manual that the Tiger had _FAR_ more than the required minimum cooling inlet opening. Bought some foil-faced rigid fiberglass insulation, and insulated the inside of the door. Reduced the inlet opening by 2/3's (still almost twice what Onan requires).

Since then, I've installed insulation on all sides of the compartment (quieter inside and out), added rubber sheet washers under the mounting points, and made other improvements.

Yeah, Onan could and should do better. But so could the RV maker; it's not all Onan's fault.

Jim, "Some days the best thing about my job is that the chair spins."

I've had many comments on how quiet my 5500 Onan is. 1800 rpm and gets slightly louder under full load but it's a low frequency sound that can hardly be heard on the curb side.

I ran mine a couple of hours yesterday preparing for a trip to Florida and it still makes a racket especially inside my garage. Had the BIG door open and it was still deafening.