Honda Generator Surging – 5 Minute fix

By: Author John Cunningham. Published: 2021/06/28 at 7:47 am

A Honda engine is as reliable as an 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 from happening in the future.

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:

• Surging
• Revving up and down
• Erratic idle
• Engine loses power under load
• The engine starts but dies
• The 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. Honda engines are really nice to work on, as you are about to find out.

Tools you’ll need:

• Phillips (star) head screwdriver
• Flathead 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 is as follows:

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 adjusts the rpm at idle; it doesn’t adjust the fuel mix ratio.

To adjust, start the engine:

How To Prevent Surging

The root 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 open-to-atmosphere fuel systems.

Meaning the gas tank is vented, unlike car and truck gas tanks. The second part of 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 the atmosphere, contaminants enter, and gas evaporates. This usually results in a sludge deposit inside the carburetor that blocks up tiny passageways.

Common symptoms include:

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

Add Gas Stabilizer

There’s a simple solution: add a gas stabilizer to the gas tank. The 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.” You’ll find a video here that covers mixing and adding gas stabilizers.

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
• 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 worn – replace
• Cracked plastic intake manifold – replace manifold
• Burnt valve – replace the valve
• Blown head gasket – replace the 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:

The generator won’t start after an oil change

The generator starts then dies

Generator Troubleshooting