Honda Generator Surging – 5 Minute fix

A Honda engine is as reliable as old pair of corduroy trousers. I’ve worked on tons of their engines, strapped to in all kinds of garden tools. They build quality kit, but you already know that.

A blocked idle jet is the most common cause of a surging Honda generator. Removing and cleaning the jet will fix the problem.

In this post you’ll learn why your Honda generator is surging, how you can fix it in just a few minutes and importantly how you can prevent it happening in the future.

Blocked idle jet

Why The Surging

Our Honda engine is running, so obviously it’s getting gas. But the surging tells us it’s just not getting enough gas. Insufficient gas supply is however a symptom and not the root cause.

In the workshop we would describe insufficient gas as fuel starvation.

Common symptoms and customer descriptions of fuel starvation, include:

Revving up and down
Erratic idle
Engine loses power under load
Engine starts but dies
Engine won’t idle

Customers use many ways to describe it, but all agree, it’s a pain in the ass.

Okay, so we know surging is caused by fuel starvation, but what’s causing the starvation?

Well, there are many possible reasons, and there are a few very likely ones. We’ll look at them all in this post, but first we’ll look at the most likely – the aforementioned blocked idle jet.

How To fix Honda Generator Surging

I know the Honda engineers care, it shows in their attention to detail. A typical example is how few tools you’ll need to perform this repair.

The engines are really nice to work on as you are about to find out.

Tools you’ll need:

Phillips (star) head screwdriver
Flat head screwdriver
Wire brush
Carburetor cleaner

To nail this repair successfully we’ll be removing, cleaning and refitting the idle jet. But to do that we’ll need to remove the idle speed control screw. The idle screw adjusts the idle speed of the engine. It’s important to return the screw to the same position (or close).

To do that we’ll need to count the number of turns when removing. To make the task easier, mark the screwdriver handle with paint and simply count the number of rotations. 

The complete process as follows:

Using a Philips (star) screwdriver, remove the idle adjustment screw by turning counterclockwise (count turns)
Using a flat screwdriver, pry up the idle jet
Using a wire brush strand, clean the idle jet orifices.
Using a wire strand, clean the carburetor idle jet orifice
Spray both the jet and carburetor orifices using carburetor cleaner and straw
Rebuild in reverse order remembering to refit the idle screw to the same number of turns

Locate the screw and idle jet

Count number of turns

Pry the jet free

Go ahead and clean it

I use wire brush strand

Clean the carburetor idle port

A can of carburetor cleaner using the straw works great when the carb is still bolted to the engine. Carburetor removed here for demo.

Adjust idle

Refit the idle jet and screw. Set the idle screw to the same number of turns as removed.
The idle screw simply adjusts the rpm at idle, it doesn’t adjust fuel mix ratio.
To adjust, start the engine:

Idles too low – turn clockwise
Idles too high – turn counterclockwise

preventing surging

The route cause of surging is often stale gas. Generators by their nature are routinely left unused for months on end and that’s where fuel starvation issues begin.

Small engines have a hard time with blended gas because small engines employ an open to atmosphere fuel systems.

Meaning the gas tank is vented, unlike car and truck gas tanks. The second part to this perfect storm is blended gas, it begins to go stale after just one month.

Ethanol attracts moisture and because small engine gas tanks are open to atmosphere, contaminants enter and gas evaporates. This usually results in a sludge deposit inside the carburetor that blocks up tiny passageways. Symptoms include no start 

Common symptoms include:

No start after a layup
Starting and dying
Lack of power under load

add gas stabilizer

There’s a simple solution, add a gas stabilizer to the gas tank. 

Gas stabilizer is a special formulation that keeps gas fresh for up to two years and protects the plastic and rubber fuel system components from the corrosive effects of ethanol.

You can find the gas stabilizer I use here on the “Generator maintenance tools page”.

Add gas stabilizer as follows:

Add 1/2 oz. (1 tablespoon) to gallon fresh gas
Shake can
Fill empty (or almost) generator gas tank
Run engine for five minutes


That’s how easy it is, now your generator is protected from gumming and plastic and rubber degradation. But just as importantly, it will start when you need it most.

Other Possible Causes of Surging

We already covered the most likely reason your Honda generator is surging but, as you know, it’s not the only reason.

It’s true, bad gas can cause other components of the fuel system to become blocked causing a restriction. But there are a few non gas related issues that can also cause surging.
Here’s the complete list:

Blocked carburetor main jet – remove & clean
Blocked carburetor bowl – remove & clean or replace
Blocked float needle – replace
Faulty carburetor – replace

Contaminated carburetor

Blocked gas filter – replace
Perished gas line – replace
Blocked gas tank – clean

Bad gas cap – replace
Spark plug issue – remove, clean and gap or replace
Valve lash out of spec – adjust valve lash

Armature issue – replace
Leaking carburetor interface gaskets – replace gaskets

Carburetor Gaskets

Cracked plastic intake manifold – replace manifold
Burnt valve – replace valve
Blown head gasket – replace gasket

I’ve included relevant links to other articles that may or may not be a generator, but that’s okay, many procedures are close to identical.

You may find these other posts useful:

Generator won’t start after oil change

Generator starts then dies

Generator Troubleshooting Page

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