Engine surge, generator

[tealboy]

Do you know what the cause of engine surge is on my inverter generator? It is 28oo watts and with no load or eco mode off, it runs smooth. Or, a heavy load, it runs smooth. However, with a low to medium load, like a heater on low or medium, the engine revs up but never really settles into a smooth run. It’s not terrible but it’s not normal either. A bit of excess virbration from the motor and a modest amount, but very noticeable amount if surging exists.

[MrWizard]

Where did the OP say it was a Honda?
Does Honda sell a 2800watt inverter model?

The posted info about Honda carburetor simplicity is all good,
And I think most Chinese built generators have similar if not identical carburetor

I just don't see anyplace where the OP said it was a Honda

I know my champion inverter generators have stepper motor controlled carburetor, not throttle linkage governor controlled carbs
At very low loads and econ 'on' the 2000i sounds like it is hunting,
The problem is the speed control programming
The first step up in speed is more than what is needed, but it's not happy running 'in first gear idle mode', so it goes up then back down repeat to infinity
And not a dang thing to be done about it
It's let it be, or play with the choke,
Or throw on more load, like a small fan

[Gdetrailer]

profdant139 wrote:

It is shocking to me that Honda and other major manufacturers have not made a carb that will not get clogged by ethanol.

Honda carbs are actually the most simple carb design you can get and surprisingly works very well.

In any carb, you WILL have something with a very small hole or a combination of small holes, that is needed in order to vaporize the gas from liquid to vapor efficiently.

The Honda design uses a jet at the bottom of the tube, which feeds the small brass tube which protrudes into the air stream right behind the choke butterfly.

Air moving over the brass tube creates a vacuum in that tube which draws fuel up from bowl through the main jet into the tube and the little tiny holes in the tube break up the solid fuel, mixing the air and fuel at the correct ratio.

It only takes one of those small holes in the brass tube to clog and the engine will not run correctly.

There is no adjustments, no fuel/air mixture screws or other small passages to clog up or need to be cleaned.

Your advice to use the gen regularly and/or drain the fuel bowl are spot on, that is the only way to reduce the amount of times you will need to remove the jet and tub and clean.

I would caution anyone who does need to clean the brass tube, try not to widen the holes, doing so will change the air/fuel mixture.

I was able to just use the pressure of a can of carb cleaner with the plastic "straw" on mine which is the safest way to clean the tube. I just held the straw to the jet end of the tube then gave a couple of good sprays. Stuff popped out and once all the holes sprayed carb cleaner I was done.

Poking metal objects like sewing needles in the holes or using tiny drill bits or even oxy/acc torch tip cleaners may affect the diameter of these holes.

[profdant139]

tealboy, you probably already know this -- but to prevent this from happening again, use gas without ethanol if you can find it. If not, add SeaFoam or Stabil to your gas tank. And "exercise" your generator monthly under load in order to keep the carb clean. Finally, drain the carb after every use.

Yes, this is all a pain in the neck. And yes, you might be able to get away with doing some but not all of the tasks mentioned above. But if you live in a place where ethanol-free gas is hard to find (as I do), take as many precautions as you can to avoid clogged jets.

I spent a lot of money getting my carb cleaned until my local mechanic took pity on me and told me what to do. I have not been back to see him in several years.

It is shocking to me that Honda and other major manufacturers have not made a carb that will not get clogged by ethanol.

[dieseltruckdriv]

Gdetrailer wrote:


Baloney.

Honda carbs do not "need" to be removed to fix them, the typical issue with especially the Honda carb design is the "main jet" clogging.

This jet is easily accessed simply by removing the fuel bowl.

The using a flat blade screw driver you STICK the screw driver right up the center where the fuel bowl screw goes into.

Then you unscrew the jet.

Carefully remove the screwdriver and the jet plus the tube should fall right out.

Observe the order and direction of the parts that came out, you will need to ensure you put them back in correctly when done cleaning.

Then with a can of carb cleaner SPRAY OPEN the tiny holes in the tube and jet.

Reassemble once every hole in the jet tube is open.

You do not need special tools, you do not need ultrasonic cleaners you should not need gaskets since the bowl gasket is resuable.

Just need to take care to ensure you do not loose any of the small parts.

That's it, there is not hidden passages in this carb to warrant such drastic measures of ultrasonic bath.

This is as simple of a carb as you can get, the only downside to it is just how easy it is to clog the main jet.

Honda dealers repair shops must make a killing on these..

If all else fails, you can actually buy brand new Honda carbs dirt cheap and even better yet is the fact that all of the Chinese Honda clone engines use this same Honda designed carb and they are even cheaper ($19-$29) than the Honda brand and will bolt up and work just as well.. There are a few variations but you can typically eyeball them and find the correct carb..

There is no mystery, no smoke and mirrors and no Baloney needed for this fix.

You can even find videos on Ytube that will show you step by step on how to clean this carb design.

I agree.

I bought my second Honda EU2000i cheap because it would only run if you left it on half choke. I knew what the problem was and how easy it was to fix so I grabbed it.

I use a bristle from a brass brush from Harbor Freight to clean the emulsion tube holes. You do have to make sure to get EVERYTHING out of them, good enough isn't with these. Don't ask. 😉

[Gdetrailer]

theoldwizard1 wrote:

tealboy wrote:
Thx. I found a thread on the Honda surging and it took me to a video. Sounds like the low speed Jet is the culprit.

This problem (also called "throttle/governor hunting") is very common in small, carbureted engines. First, the carburetors are set as lean as possible from the factory. Second the jets are fixed, not adjustable.

The term "low speed jet" is really not correct. It is the PRIMARY jet. "Low speed" makes you think that it is only used at lower RPMs. In fact it is ALWAYS used and establishes the "base" fuel flow.

Cleaning small engine carburetors can be a challenge. They MUST be removed from the engine and disassembled. Take care not to tear any gaskets as they can be reused multiple times (buy spares or gasket paper with a good sharp X-Acto knife). Heated ultrasonic cleaner is the best tool, but unless you do dozens per minth, they are not worth the cost. A 1 gallon bucket of carburetor cleaner and an over night soak is also good.

Or place the disassembled carburetor in a pot of water with some lemon/lime juice or vinegar or a few drops of Dawn dish soap and boil for about 10 minutes. Probe all passages/jets with a single wire from a wire brush. Blow out.

Baloney.

Honda carbs do not "need" to be removed to fix them, the typical issue with especially the Honda carb design is the "main jet" clogging.

This jet is easily accessed simply by removing the fuel bowl.

The using a flat blade screw driver you STICK the screw driver right up the center where the fuel bowl screw goes into.

Then you unscrew the jet.

Carefully remove the screwdriver and the jet plus the tube should fall right out.

Observe the order and direction of the parts that came out, you will need to ensure you put them back in correctly when done cleaning.

Then with a can of carb cleaner SPRAY OPEN the tiny holes in the tube and jet.

Reassemble once every hole in the jet tube is open.

You do not need special tools, you do not need ultrasonic cleaners you should not need gaskets since the bowl gasket is resuable.

Just need to take care to ensure you do not loose any of the small parts.

That's it, there is not hidden passages in this carb to warrant such drastic measures of ultrasonic bath.

This is as simple of a carb as you can get, the only downside to it is just how easy it is to clog the main jet.

Honda dealers repair shops must make a killing on these..

If all else fails, you can actually buy brand new Honda carbs dirt cheap and even better yet is the fact that all of the Chinese Honda clone engines use this same Honda designed carb and they are even cheaper ($19-$29) than the Honda brand and will bolt up and work just as well.. There are a few variations but you can typically eyeball them and find the correct carb..

There is no mystery, no smoke and mirrors and no Baloney needed for this fix.

You can even find videos on Ytube that will show you step by step on how to clean this carb design.

[theoldwizard1]

Lynnmor wrote:
DO NOT probe jets with wire, use a bristle from a paint brush. Wire will scratch the tiny bores of these jets causing a change of flow rate.

I have been doing it for years ! A paint brush bristle is too soft. A wire brush bristle is stiff yet will bend with a small amount of force.

[Lynnmor]

DO NOT probe jets with wire, use a bristle from a paint brush. Wire will scratch the tiny bores of these jets causing a change of flow rate.

[tealboy]

theoldwizard1 wrote:

tealboy wrote:
Thx. I found a thread on the Honda surging and it took me to a video. Sounds like the low speed Jet is the culprit.

This problem (also called "throttle/governor hunting") is very common in small, carbureted engines. First, the carburetors are set as lean as possible from the factory. Second the jets are fixed, not adjustable.

The term "low speed jet" is really not correct. It is the PRIMARY jet. "Low speed" makes you think that it is only used at lower RPMs. In fact it is ALWAYS used and establishes the "base" fuel flow.

Cleaning small engine carburetors can be a challenge. They MUST be removed from the engine and disassembled. Take care not to tear any gaskets as they can be reused multiple times (buy spares or gasket paper with a good sharp X-Acto knife). Heated ultrasonic cleaner is the best tool, but unless you do dozens per minth, they are not worth the cost. A 1 gallon bucket of carburetor cleaner and an over night soak is also good.

Or place the disassembled carburetor in a pot of water with some lemon/lime juice or vinegar or a few drops of Dawn dish soap and boil for about 10 minutes. Probe all passages/jets with a single wire from a wire brush. Blow out.

Very helpful, thank you.

[theoldwizard1]

tealboy wrote:
Thx. I found a thread on the Honda surging and it took me to a video. Sounds like the low speed Jet is the culprit.

This problem (also called "throttle/governor hunting") is very common in small, carbureted engines. First, the carburetors are set as lean as possible from the factory. Second the jets are fixed, not adjustable.

The term "low speed jet" is really not correct. It is the PRIMARY jet. "Low speed" makes you think that it is only used at lower RPMs. In fact it is ALWAYS used and establishes the "base" fuel flow.

Cleaning small engine carburetors can be a challenge. They MUST be removed from the engine and disassembled. Take care not to tear any gaskets as they can be reused multiple times (buy spares or gasket paper with a good sharp X-Acto knife). Heated ultrasonic cleaner is the best tool, but unless you do dozens per minth, they are not worth the cost. A 1 gallon bucket of carburetor cleaner and an over night soak is also good.

Or place the disassembled carburetor in a pot of water with some lemon/lime juice or vinegar or a few drops of Dawn dish soap and boil for about 10 minutes. Probe all passages/jets with a single wire from a wire brush. Blow out.

[tealboy]

RLS7201 wrote:
That surge is called a "lean roll". The carb is running lean because of an obstruction in the carb.

Richard

Thx. I found a thread on the Honda surging and it took me to a video. Sounds like the low speed Jet is the culprit. Also appears to be easy to clean. Remove the low speed adj screw and pop the low speed jet out, clean the small hole and back together it goes.

[RLS7201]

That surge is called a "lean roll". The carb is running lean because of an obstruction in the carb.

Richard

[2oldman]

Has it been stored with gas in it?