The infamous GCV160 AutoChoke

[Salex]

My GCV 160 bought in October 2020 started doing the exact same thing when I started it up again last spring, 2021. Is there an answer to the problem?

 

[olgeezershonda]

Yes there is, replace the faulty thermowax actuator .

 

[enigma-2]

I would recommend adding Sea Foam (at 2x normal dosage) to your gas. Run the engine to draw the mix into the carburetor then shut off and let it soak. Sea Foam will eventually dissolve the clogs in the tiny jets in the carb (what i believe is causing to problem. Probably due to the use of Ethanol gas at some time).

I had to let a snow blower sit for a week once before the engine would idle again. (It was really clogged,).

 

[mikehouse]

Hi all.Enjoyed reading all responses.All were very intersting.In the beginning the original poster said he was using g Ethanol-free gas,but didn't say octane level.Should be 92 or 93.On Seafoam,I also agree,but also he said the mower was new.
I have the same exact engine on a Husavarna HU700F with none of these issues.Other than checking fuel line going TO the carb for erosion,I'm stumped.
Hoping an answer is found and shared.

 

[olgeezershonda]

Hi all.Enjoyed reading all responses.All were very intersting.In the beginning the original poster said he was using g Ethanol-free gas,but didn't say octane level.Should be 92 or 93.On Seafoam,I also agree,but also he said the mower was new.
I have the same exact engine on a Husavarna HU700F with none of these issues.Other than checking fuel line going TO the carb for erosion,I'm stumped.
Hoping an answer is found and shared.

Try and find your owners manual. Unless specified otherwise Honda says you can use use regular unleaded, 86 octane (or higher) pump gas with no more than 10% ethanol content. You didn't say what issues you are having so I'm not even going to try and guess.

 

[bertsmobile1]

Hi all.Enjoyed reading all responses.All were very intersting.In the beginning the original poster said he was using g Ethanol-free gas,but didn't say octane level.Should be 92 or 93.On Seafoam,I also agree,but also he said the mower was new.
I have the same exact engine on a Husavarna HU700F with none of these issues.Other than checking fuel line going TO the carb for erosion,I'm stumped.
Hoping an answer is found and shared.

Fuel and particularly fuel deteroriation is location & weather dependent.
So some will have massive problems with it and others will wonder what the heck all them idiots are rabbiting on about .
The classic example is my landlord live 500 yards from my workshop and 30' higher
We both ride motorcycles
We can both fill up from the same service station and often the same pump.
A month latter his fuel has gone off while mine will be fine for better than 6 months .
magic fluids like seafoam, startron & all the others are rather like NY elephant repellent.
They usually work but 99% of those using them don't need to use them which gives the false impression that they are a cure all .
Good thing is they will do no harm
Bad thing is they do not work all the time and that usually happens where they are needed most .

 

[enigma-2]

On Seafoam,I also agree,but also he said the mower was new.

Chuckle. Couple of years ago I bought a new Simplicity garden tractor. It ran ok for a few days and then wouldn't idle.

Talked with my dealer and learned he had put Ethanol gas in it to display it at the county fair. Afterwards it had sit for a few weeks in his lot.

Tried Sea Foam and it helped a little. Dealer picked it up and ran the carb parts through his ultrasonic cleaner. Didn't help. Finally disassembled again and manually rodded out all of the tiny holes and passages with carb wires and that fixed it. Ethanol will crap a carburetor in only a month.

I've found that if I use Sta-Bil in the gas can as I fill up at the pump and add a small amount of Sea Foam, never have a problem. (Including gas that sits in my generator for over a year at a time).

Have used Sea Foam for years but seen a YouTube video about Star Brite. So I'll try it next and see if it's better.

 

[bertsmobile1]

You seem to have missed the point.
What works for you might not work for your neighbour and visa versa

Just noticed this post has 50,000 views and 8 replies since 2016. Amazing......

slomo

Well there has been over 100,000 people on this list and lot of them probably read every post in the sections for the mowers they have.
So no surprise
Oh and where will be web crawlers & spiders that "read" the posts as well and they probably account for at least 1/2 the views .

 

[bertsmobile1]

Surging is just about always a fuel problem.
It happens because the fuel:air ratio is too low to sustain a constantant speed so the engine slows down
The governor then slackens off allowing the throttle to open up.
The sudden rush of air through the carb causes excessive fuel to be drawn into the engine.
This is intentional, to aid acceleration.
If you pop a colour tune into you car engine you will see , even in a fuel injected engine, the flame colour will go too rich ( yellow ) briefly whenever the throttle is opened up .
So back to your engine
The enrichment from the sudden increase in air flow, is only temporary so when the governor kicks in and closes the throttle to maintain the ~ 3,000 rpm your engine is back where it started from.
The other thing that can happen which looks similar but is different is choke flutter which of course only happens on autochoke models.
It sort of looks & sounds the same but you get black smoke from the muffler because in place of being too lean, the engine is too rich.
When reading forum posts you always have to be careful as a lot of people have no idea what the part they are looking at actually is so when they say the auto choke is moving back & forth , they are usually looking at the governor.
A lot of people see the throttle butterfly & think it is a choke & visa versa.

Now things that make the mixture lean are not enough fuel being added in the first place. or air entering after the fuel has been added.
The latter will be an air leak from a loose mounting bolt, torn or incorrect placed gasket, cracked manifold , etc.
Not enough fuel is generally caused by a restriction in the fuel passages ( partially blocked jets ) but a low fuel level in the float chamber or blocked bowl vent will also restrict fuel flow.
After that then you are looking at the fuel supply to the carburettor and that can have crud stuck in the tank, of fuel lines or collapsed fuel lines or pinched fuel lines .

Now the only thing that any magic goo will do is dissolve some of the varnish like deposits and they account for a small amount of fuel problems that come into my workshop and generally are seen at the beginning of the season or on products that are stored incorrectly for a very long time.

The important thing is to rule nothing out till you have checked.
I had a brand new mower, bought off the floor from a major retailer that had random surging problems
After at least 5 trips into the workshop I finally removed the fuel tank and checked inside.
I found 3 toffee wrappers inside the tank , probably placed in there by a child who was told "Don't toss those lolly wrappers on the floor" so they found a convienent hole to put them in .

Being a new mower it could have been missing a gasket, had a loose mounting bolt . or the bolts done up to different torques.

The choke could be failing to open fully or to stay fully open

Or it could be bad fuel that was off before it was pumped into your fuel can or even a bad plug because the bad fuel had allowed a conductive path to form down the side of the electrode .

 

[mikehouse]

Hey all, great forum here! Thanks for all the info I've learned so far about my mower.

Here's the deal, I bought a new GCV160 powered mower this Spring, it isn't used a lot, I only run non-ethanol fuel in it much like all of my craftsman power equipment. The first time or two I used it, less than 1 hour, it ran fine. After that, the mower would start on first pull, run great for a few minutes, and then as it warmed up, the autochoke starts surging. Being the mower is so new, I took it to the local Honda repair center, they said it was fixed, I brought it home. The mower literally only gets used for trim work where the riding mower can't get to.

Let it sit for about a week before filling it up with new gas, and going about my business. Low and behold, exact same issue, like nothing was fixed at all. It only surges once it's warmed up. I just can't put my finger on what could be wrong, my guess is that they replaced the wax cylinder, but apparently that has had no effect. I read one thread where someone adjusted the autochoke 'rod' but can't find any information anywhere on doing that. All of the posts on here seem to be about starting or surging before it warms up. Mine is the opposite, fine on starting and cold, once it warms up it surges.

Any suggestions? I'd really love not to take it back to the dealer, who is a 45 minute drive each way (x4 to drop it off and pick it up). The mower easily has less than 5 hours runtime on it.

Thanks again!

Since it only happens when fueled,could it be THAT particular fuel? Try a different gas station.