Honda Generator Surging Under load only

[Razorhunter]

Honda EM5000S generator in seemingly excellent condition, and has good fuel, air filter, spark plug. Generator does not surge at idle. Only surges under a load, and it's not always a consistent surge, meaning it will fluctuate slightly, and come and go. I can hold my hand on the governor arm/linkage assembly and somewhat stop the surging to a degree.
Is this typically indicative of a dirty carb and if so, what's the chances I can go in and handle the issue and back out, without spare gaskets/seals/etc?
This is a GX340 engine.
Also, what's the chances this is just the governor springs/arms up top? Is there a possibility that this is just the springs or arms out of adjustment, or is this always a lack of fuel, or too much air issue? What's the chances this is one of the "hidden" screen/filters these Honda engineers seemingly put somewhere within the fuel line I read about? My fuel sediment bowl was clean as a whistle. I have not found the other screen I keep reading about. I'll have to do more digging on parts diagrams to find this screen that should be checked for cleaning. Possibly it's above the fuel shut off valve in the tank bung?
I have honestly never messed with these carbs or had problems in almost 50yrs of being alive. Many a chainsaw carb issue, but never a 4 cycle carb issue to speak of. Guess I've been blessed.

ETA: Can someone confirm that the phillips adjustment screw on the governor linkage directly above carb is strictly for the idle adjustment zone? I read that somewhere this is the case, but I honestly don't know what that phillips screw adjusts, but it's definitely tied in with the governor linkage. NOTE I am NOT talking about the actual governor shaft that has the wrenching flat and the 10mm locknut on it, which is over under the fuel tank about 8"-10" away. This phillips screw adjustment to governor linkage is directly over the carb.
Thanks for any help. Honestly never had this issue before, but the minute I go and buy a used generator, it was bound to happen at some point, so all is well.

 

[rust in the eye]

The surging is probably due to a lean condition so your thoughts of a dirty carb seem spot on but don't rule out a vacuum leak.
My experience is the gaskets survive disassembly as often as not. If you need the machine to be up and running buy the gaskets beforehand.

 

[larry_g]

One good source of information is James Condon on the utube. https://www.youtube.com/@jcondon1

lg
no neat sig line

 

[The Cobbler]

This phillips screw adjustment to governor linkage is directly over the carb.

picture would help .
as above poster said, James Condon is a wealth of knowledge . I think he has had some doing that that needed a slight adjustment of the governor

 

[Steve_P]

Agree that this is a typical indicator of a carburetor issue, usually a partially clogged jet or drilled passage. This is extremely common on snowblowers that still have last year's gas in it.

 

[mm08822]

It could be a dirty carb with simply a piece of small debris partially blocking the port controlled by the float. Drop the bowl and inspect.

Also note if debris in the fuel drained from the bowl.

Check the fuel filter and look for **** in the bottom of the tank.

Afterwards run carb cleaner in the gas.

Always run engine dry before putting away. I run mine dry with fuel containing stabilizer.

 

[Sumboodie]

One good source of information is James Condon on the utube. https://www.youtube.com/@jcondon1

lg
no neat sig line

I thought it was Condom. Guess never paid close attention

 

[Steel_Rain]

What's the chances this is one of the "hidden" screen/filters these Honda engineers seemingly put somewhere within the fuel line I read about?

I’m pretty certain the GX motors all use the “in hose” inline filter at the bottom of the tank. Take the fuel line off the base of the fuel tank and you will see a 2” filter inside the fuel line. Obviously make sure that’s clear.

Before you do any of that, let it run without a load spray carb or brake cleaner around the carb/intake to see if the engine speed changes. You could have an air intake leak, exposed when under load.

Other items to check are the carb bowl, make sure the bottom screw is tight (not over tight).

Have you made any adjustments to the mixture screw?

Regardless, this is fueling problem.

 

[finn]

It’s lean.

Contrary to JG legend, Honda engines are susceptible to carb issues, just like every other gasoline engine on the market.

They don’t hold an exemption card issued at birth.

The Honda engine on my wife’s lawnmower is due for a carb freshening, too.

 

[theoldwizard1]

Contrary to JG legend, Honda engines are susceptible to carb issues, just like every other gasoline engine on the market.

Big fan of James Condon ! Buddy had a "well used" pressure washer with a Genuine Honda engine. Hard to start and surged. Clearly running lean, likely the idle/pilot jet ! Popped it out, Couldn't get any spray through it. Luckily I had some number drills and ran a #76 through it. Started first pull. Ran good !

After you have double checked everything, find a number drill that fits and drill it out 1 - 2 sizes larger !

 

[rharman]

Paging @Metallitubby ....

 

[Rinspeed]

A healthy dose of Seafoam might clear things up.

 

[Razorhunter]

Ok so yes it turns out this was a dirty jet in the carb. I cleaned it and problem solved.
I wish parts were readily available for these carbs honestly. Maybe they are and I just don’t know it. I did find the gasket kit but that’s it.
Here is a pic of the adjustment screw (not mounted to the carb mind you) which has something to do with the governor linkage. It’s located directly behind air filter box up top under the tank on the left side opposite of the actual governor vertical rod adjustment.
Still not sure what this thing does.
Should I be checking the hertz output frequency of this generator? I’ve read that’s a thing to do after people have messed with the governor.

 

[Razorhunter]

To the guy who said to drill and bore the jet out oversized….Is that really a thing on generators? I assume it’s not really an engine performance mod, but rather just creating a larger hole so as to make it less likely for the jet to clog up in the future??? Please explain.
Here’s one final amateur question… If I’m using ethanol free gas and also stabil, at what point does this gas expire? Can it ever gum up and clog a carb? I have always wondered this.

 

[sqznby]

I have used torch tip cleaners in the past to clean some of the passages but never drilled any out.
I use CRC Mass airflow cleaner to clean all of my carbs and 99 percent of the time I never even remove the carb. Pull the filter and the bowl and spray directly in every orifice of the carb and up through the pickup and done.

 

[Metallitubby]

To the guy who said to drill and bore the jet out oversized….Is that really a thing on generators?

At Honda, we don't recommend it, but most of us oversize mains. Some of the better carburetor tools have a knurled "wire" that makes just the right amount of adjustment to keep it from happening again in the future.

*Also note that when cleaning Honda carburetors, people often forget the transfer and/or pilot jets, which is usually why one "comes back".

 

[Razorhunter]

At Honda, we don't recommend it, but most of us oversize mains. Some of the better carburetor tools have a knurled "wire" that makes just the right amount of adjustment to keep it from happening again in the future.

*Also note that when cleaning Honda carburetors, people often forget the transfer and/or pilot jets, which is usually why one "comes back".

Is that the one that the float opens/closes? I actually forgot to clean this one than the float controls but engine is running fine.

 

[Metallitubby]

Is that the one that the float opens/closes? I actually forgot to clean this one than the float controls but engine is running fine.

No, it's the black, nylon "T-shaped" plug on the side of the carburetor just under the throttle-stop.

 

[Rinspeed]

Is that the one that the float opens/closes? I actually forgot to clean this one than the float controls but engine is running fine.

That's your float needle, all it does is stop the flow of gas into the bowl when the floats get to a certain level. If you have a carb that flows gas onto the floor it possible the float needle is damaged, the seat the float needle goes into is damaged or the float level needs to be adjusted down lower. Sometimes a float can get a very small leak in them and not work correctly either so it's always a good idea when you have a carb apart to throw the floats in a bowl of water to check for any pinhole leaks.

 

[Retired dozer fixer]

Ok so yes it turns out this was a dirty jet in the carb. I cleaned it and problem solved.
I wish parts were readily available for these carbs honestly. Maybe they are and I just don’t know it. I did find the gasket kit but that’s it.
Here is a pic of the adjustment screw (not mounted to the carb mind you) which has something to do with the governor linkage. It’s located directly behind air filter box up top under the tank on the left side opposite of the actual governor vertical rod adjustment.
Still not sure what this thing does.
Should I be checking the hertz output frequency of this generator? I’ve read that’s a thing to do after people have messed with the governor.

Hertz or frequency is more important than voltage. I had to adjust my generator speed after installing a new carb. Set it at 61.9-62 at no load. When under load it was 59.7 at about half load. Around 5KW on a 10KW generator. This gen has about 1350 hours on it and it’s only 2 years old. Replaced because of worn linkages and shafts. Plastic parts and vibration aren’t a good combination

 

[tak1313]

Just an fyi for gasket (at least intake gaskets). I have found that if I am unable to find or obtain an intake gasket right away, something like Hylomar does wonders. It was developed for racing decades ago, is non-hardening, and doesn't "glue" the gasket like other dressings which makes it easy to remove/clean when you're actually able to obtain a new gasket (or just leave it as is).

 

[308guru]

To the guy who said to drill and bore the jet out oversized….Is that really a thing on generators? I assume it’s not really an engine performance mod, but rather just creating a larger hole so as to make it less likely for the jet to clog up in the future??? Please explain.
Here’s one final amateur question… If I’m using ethanol free gas and also stabil, at what point does this gas expire? Can it ever gum up and clog a carb? I have always wondered this.

Drilling out a jet, or even suggesting it, is just plain stupid. It's a metering device, not some random hole through a chunk of brass. The difference in jet sizes are often tenths of a thousandth. The bores (on quality brand manufacturer jets) have a nice surface finish on the ID, not something achieved by Billy Bob with his 10 piece Ryobi drill set.

 

[The Cobbler]

Drilling out a jet, or even suggesting it, is just plain stupid. It's a metering device, not some random hole through a chunk of brass. The difference in jet sizes are often tenths of a thousandth. The bores (on quality brand manufacturer jets) have a nice surface finish on the ID, not something achieved by Billy Bob with his 10 piece Ryobi drill set.

drilling jets happens a lot more than you probably imagine. and it's not stupid if you know what youre doing .
it's often a necessary by product of non adjustable carburetors

 

[finn]

Drilling out a jet, or even suggesting it, is just plain stupid. It's a metering device, not some random hole through a chunk of brass. The difference in jet sizes are often tenths of a thousandth. The bores (on quality brand manufacturer jets) have a nice surface finish on the ID, not something achieved by Billy Bob with his 10 piece Ryobi drill set.

SeaFoam says (on the can) it’s good for two years as a gas stabilizer when mixed at the recommended dose.

I was having issues with fuel induced (I think) misfiring on the Kawasaki Teryx this week that had half a tank of last years (no ethanol ) gas left in it. A dose of Sea Foam cleared it up, at least it seems to have.

The boat has the same, seemingly fuel related misfire. I’ll throw the rest of the can in the tank and see if that helps before I take it out of the water and drain the tank.

A few years ago I had an early winter misfire on a Tecumseh Snow King snow thrower engine, but I threw in some Berryman’s fuel additive and cleared it up. I think the Berryman’s is actually better than SeaFoam.

Standard procedure is to run the equipment out of fuel prior to storage, but that’s not always practical, and I’m reluctant to do that on fuel injected engines like the Teryx or boat.

 

[theoldwizard1]

drilling jets happens a lot more than you probably imagine. and it's not stupid if you know what youre doing .
it's often a necessary by product of non adjustable carburetors

Use number drills. Find the one that fits the current hole and then go up 1 or 2 sizes.