My generator is surging

[dperkinstx]

I have an Onan Emerald Plus 4000 generator. It isn't running very well. From what I've read, I'm pretty sure I need to remove the bowl and clean the jet. Everywhere I've search, I'm reading there's a nut on the bottom of the bowl. Mine has a plastic piece. I can't get that piece off without breaking it. How do I get the bowl off the carb?

[Toot_Mc]

First thing to check if surging is the Air Filter, that always helped mine run better. For some reason the compartments where Gen sets are placed seem to attract a lot of dirt and dust.

[Sam_Spade]

midnightsadie wrote:
maybe a can of sea foam would fix it ,sea foam will eat gunk.

A much better cleaner is Berrymans B12 Chemtool.

But whatever you use, "a can" probably isn't the right dose; follow the instructions on the can. If the gen shares fuel with the engine, it might take several cans.

Also, how bad is the "surge" ?
I've got the same model and it flutters a little at full load.
Drops from about 120 unloaded down to 112 at full load and there it vaires about 2 Volts up and down. This is with a new carb so I assume that it is mostly normal.

And finally, before anyone pays to have a carb on an Onan cleaned, find a dealer and ask the price of a new carb. I was surprised to find that the cost is about the same.

[bounder39zman]

the plastic piece is a limiter cap to allow a 1/4 turn mixture adjustment for high altitude usage. It will come off as OP stated, by prying with screwdriver, careful to not bend mixture screw. after removal turn screw in until gently seated, counting turns, so you may get adjustment correct after reinstalling...usually about 1-1/2 turns.
If your generator sat idle, without being run for extended period, more than 6 months, with bad gas in it, the carb. will probably have to be removed and completely disassembled and cleaned. There are lots of tiny passages that can plug up and make generator "surge". Also, common cause of surging on this model is Intake manifold developing vacuum leaks, causing lean mixture, especially at low loads.
btw, pic of carb posted by mudchucker is not from Emerald model, but later model HGJAB genset

[midnightsadie]

maybe a can of sea foam would fix it ,sea foam will eat gunk.

[gbopp]

Have you changed the generator fuel filter?
I had a surging problem on our 96 Southwind, Onan 5500. A new filter took care of it.

[copeland343]

Take a small screwdriver and pry in several places between the bowl and plastic. It will come off. I have the same generator.

[MudChucker]

not the best photo.

On some the bottom piece where you have plastic is just a drain. depending on the carb there may be 3 or 4 phillips head screws that hold the float bowl on, really apply a decent amount of screw driver down force to keep the head from stripping. Others, you need to remove that bottom piece, without breaking it 😉

Is this like yours ? youtube video clicky

[2oldman]

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