# Another only runs with choke thread



## pikeslayer (Dec 8, 2007)

I read all the "only runs with choke" threads. My GX340 is doing the same thing. Installed a new carb. Still does it. Put Permatex on all sealing surfaces between the carb and engine. Still does it. Put new fuel in it. Still does it. 

Let's talk about the governor spring:

I have a spring that goes from my "throttle" control lever to the governor arm. In other words, I control the speed of the engine by changing the tension of that spring. So when someone says "weak governor spring", what are they talking about? If it is weak, I just move the throttle adjust lever a little more to make up for the weakness, right?

This engine was originally on a concrete saw, I put it on a snowblower. Worked great for 2 years. Any ideas, or is this POS Honda is headed to the trash?


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## pikeslayer (Dec 8, 2007)

Oops, forget an introduction.

Found this forum through a google search. Looks like a lot of good info here. I'll definitely frequent this forum. Hope you guys can help.


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## 30yearTech (Sep 14, 2006)

When an engine will run with only the choke, that pretty much means it's not getting enough fuel. This generally means there is some restriction in the main jet of the carburetor, or an air leak. If you replaced the carburetor are you sure you got the right one? If the jets in the carburetor are too small it will not deliver sufficient fuel to the engine. Weak governor springs will not cause an engine to run only with the choke.


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## pikeslayer (Dec 8, 2007)

I'm with ya on the not getting enough fuel theory. I don't think I mentioned before, but when I apply choke, the surging goes away. The carb I put on came off of another GX340, so I'm pretty sure its the right one.

Another thought I had was, maybe the fuel level in the bowl is too low(i.e. adjust the float). But the floats are plastic and don't adjust. I know it's getting gas, every time I swap carbs I have to drain the bowl.

I Permatexed the shit out of this thing, and I find it hard to believe that the main jet of both carbs is restricted.

One other thig, there was a point where I witnessed a blue flame pop out of the carb. Could this be an intake valve hanging open?


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## 30yearTech (Sep 14, 2006)

Could be a valve problem, or ignition timing problem, but a lean running condition can cause a backfire.

If the carburetor was not brand new I think I would tear it down and remove the nozzle and make sure it's good and clean. There could be a problem with the low speed circuit or air bleed if it's surging or hunting.


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## tommyj3 (Sep 16, 2006)

If it's got the metal fuel shut off valve on it, remove the bowl on the valve and see if there is any trash in the filter screen blocking fuel flow.


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## pikeslayer (Dec 8, 2007)

tommyj3 said:


> If it's got the metal fuel shut off valve on it, remove the bowl on the valve and see if there is any trash in the filter screen blocking fuel flow.


I have fuel in the float bowl. WOuldn't that rule out the shut off?


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## pikeslayer (Dec 8, 2007)

30yearTech said:


> Could be a valve problem, or ignition timing problem, but a lean running condition can cause a backfire.
> 
> If the carburetor was not brand new I think I would tear it down and remove the nozzle and make sure it's good and clean. There could be a problem with the low speed circuit or air bleed if it's surging or hunting.


I tore apart the original carb and couldn't find a problem. Probed every orifice with a bristle from a wire brush. Then put the "new" (no more than 2 hrs on it) carb on same behavior. That's what made me think air leak between carb and engine. Permatexed it up, same behavior.

What is the air bleed?


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## 30yearTech (Sep 14, 2006)

http://www.hobbytalk.com/bbs1/attachment.php?attachmentid=50110&stc=1
GX340_Carb.pdf

Reference number 36 is the main metering jet, #14 is the nozzle and #37 is the pilot jet or air bleed, if this is plugged or the passages leading to it, the engine will surge or hunt under no load conditions, when a load is applied it usually clears up as this circuit is bypassed. The nozzle #14 sometimes gets clogged, so if you don't remove it to make sure all the orifices are clean you can have problems.


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## Homer D Poe (Jan 6, 2004)

double check gaskets are right way around #19 on pdf is easy to flip if not having a good day. Sealant may block air leakage but if some gaskets get flipped the will cause internal leak. Love my Honda's except for the shutoff, it is poorly labeled and often in wrong position. Always have to tell customers to the right is on.


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## ogyver (Jan 10, 2011)

*Engine will run on choke only*

Had same problem with my GX340. Bought a new aftermarket carb from ebay. It would only run on choke. The original carb ran rough with black smoke and then stopped running. I bought this engine used so didn't know its history. Turned out the air metering plug( black plastic ribbed plug under the black plastic plug under the black plastic screw) was missing its lower tiny oring on the original AND the gas had gone bad after 6 months. Never figured why the new carb ran on choke only- it did LOOK identical to the B34 carb on the engine.


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## nnyparts.com (Dec 28, 2009)

When ever you need to run the choke to keep it running, its more apt to be a fuel issue.

1. Ethanol in untreated fuel
2. Carb Kit needed
3. Cracked Fuel Line
4. Primer bulb bad


Its getting to be a real pain in the backside of the ethanol doing more harm than good when it comes to small engines. Now you end up buying the treatment (around 8.00 to treat 48 gallons of gas ) on top of paying top dollar for the fuel. 

Two problems develop....one is that it will separate from gas and be on the bottom of the tank. All carb kits and gaskets are now coming through saying that it is not warranted for anything above 10% ethanol. The vast majority of small engine machines pull from the bottom of the tank first so you end up with the majority of the fuel being ethanol. It will eat the rubbers and corrode anything metal.

Second is that it loves to draw moisture. So now your out buying a second treatment for water in the gas. The majority if issues were seeing with the homeowner is now directly related to these issues. So...treat a 5 gallon container and mark it as treated and only use that.


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## Quinton (Aug 27, 2012)

*Honda GX 340 Lean Issue*

Hi. New to this site. Have read other forums of this issue. Have a Honda GX340 on a 3000 psi water blaster. Surges while running. Runs fine with choke on. Replaced- Fuel, Fuel filter, Carburetor, Carburetor base gasket, and Spark plug. Also checked valves. We have another identical pressure washer that I have swapped the new and old carburetors, 3 total, with. They all work fine on that one. I know this is a lean condition. Sprayed carb cleaner around outside of carb, only change is when i spray around where the air bleed dumps on bottom of base plate. Any ideas?


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