Last year I had hunting issues on my GX340 11.0 hp Honda. Here are the symptoms:

Idles, but hunts
When I slowly increase the speed it will hunt with larger swings then finally die.
Spark plug is sooty.

Here is what I have done:

New plug. New carb. Checked primary and secondary resistance of coil. Checked air gap of coil. Adjusted governor. Checked oil level. Bypassed oil alert circuit.

Nothing makes a difference.

Any help this year?

You have a fuel restriction which means you may have a non-venting fuel cap or you need to clean the carb, I am not familar with your engine so I can't tell you what carb kit to install, however try loosening the fuel cap to see if it helps. Have a good one. Geo

You have a fuel restriction which means you may have a non-venting fuel cap or you need to clean the carb, I am not familar with your engine so I can't tell you what carb kit to install, however try loosening the fuel cap to see if it helps. Have a good one. Geo

Thanks for the response Geo.
Fuel gushes out of the supply line on the way to my new carb. I have ran it without the cap on it, but that doesn't seem to make a difference.

possibly a small air leak somewhere between the carburetor and cylinder head. A plugged idle jet/ air bleed can also cause an engine to "Hunt", but generally will not cause it to die.

My engine is a qxc, which calls for an internally vented carb. My new carb is externally vented. Would this cause a problem. Will either carb run on this engine?

Internal or external vent should not make any difference as long as the vent is open. Some internally vented carburetors call for a different air filter element, but that should not mater if you are now using an externally vented unit.

I would try the governor adjustment again, or look for something causing the engine to run lean.

Readjusted the governor tonight. Cleaned all intake mating surfaces and installed new gaskets. Made no difference. Put the old carb back on , no difference. Is there a way to adjust the governor to get rid of the surging? I mean, can I digress from what the manual says in a direction that is likely to reduce surging?

Readjusted the governor tonight. Cleaned all intake mating surfaces and installed new gaskets. Made no difference. Put the old carb back on , no difference. Is there a way to adjust the governor to get rid of the surging? I mean, can I digress from what the manual says in a direction that is likely to reduce surging?

Nope, you cannot set the governor any other way and have it work. If the engine eventually dies, then it's not the governor it's something else. Have you checked your valve clearances?

Thanks for all your help 30yeartech. Last year I made sure I had some clearance because I thought a valve was hanging open. I will set the clearance tomorrow night.

Does choke affect it? If choke helps quell the surging, then this is what you'll find - the carb. has a restriction in it. I think what poster "Geo" meant - it's in the carb. not the fuel line. This problem is very common with Honda's. I see it all the time, and it's usually a slight gum buildup in the main jet and feed nozzle area. But as others pointed out, the 340 also sees blown head gaskets and other issues - depends on the application. Leaf blowers are often subjected to overheating conditions. I bring this up as you said it happened last year, so I figure this is a seasonal machine. Honda's with blown head gaskets usually squeak during cranking and throttle-up.

Thanks for posting Paul! The choke does help it. But the last carb I had on never saw gas before. Old carb or new will surge. I'm getting desperate. Can I drill out the main jet?

Thanks for posting Paul! The choke does help it. But the last carb I had on never saw gas before. Old carb or new will surge. I'm getting desperate. Can I drill out the main jet?

Not a good idea. If you go too big, by even a little, it'll run rich and you'll have to get a new jet to bring it back to standards. I have seen "bad" new float-style carburetors, but very, very rarely. If the carb. came from a Honda dealer, then it should be a quality one. They should also be able to work with you, if it truly is the problem - but they may want to see and possible work on it, which may cost you labor time. If you got an aftermarket carb., there may be something left to be desired.

I'd suggest you clean the jet. Removing the nozzle requires a special screwdriver, or a modified regular one. There's only a small area to catch the nozzle screwdriver slot, and it's very easy to bugger it or the surrounding thread up. So for now I'd leave the nozzle alone. You can clean the jet without removing it, but it's easy to get out and then you can check it before and after by holding it up to the light. Since you don't have Honda's jet cleaning tool, which looks like an acetelyne torch tip cleaner, if you have a bench grinder you can make one that'll work. Take a length (8") of old throttle cable inner wire, grind a taper down to a point in the last inch of one end. I grind it with a slight flat on each side, so it can scrape the gum from the jet. BUT, do not scrape too hard else you'll resize the jet larger, and need to replace it. Carb. spray-cleaners have their place, but often don't remove the tough stuff.

I digress though, in that if the new carb. doesn't change the problem, I'm thinking vacuum leak. It could be as simple as a bad intake gasket, or a cracked insulator.

Good luck!

I'm confused. What is the jet, what is the nozzle. There is a pdf floating around of the carb. What number part is the nozzle, and jet?

Thanks!

I'm confused. What is the jet, what is the nozzle. There is a pdf floating around of the carb. What number part is the nozzle, and jet?

Thanks!

On your carburetor the nozzle is the part that extends up into the throat of the carburetor, the jet screws into the carburetor just below the nozzle and has a small orifice drilled into it.

On the Honda parts break down the nozzle is ref # 14 and the jet is #36.

I think i got it. :woohoo:There is a little black plastic jet type thingy under the idle speed screw. There is a hole in the bottom of it so small light won't even shine through it. I jammed a bristle from a wire brush through it about ten times, put it back in and it quit surging. Funny thing is, I remember doing this last year to no avail. Who in the h3ll would put a hole in a carb that small with out a screen before it, like in a fuel injector.

So now that it runs I had to grind and cut, and weld in a new scraper bar on the bottom. Should be good to go, until the next sub-atomic particle finds its way into that idle jet.:thumbsup:

Thanks for the help everybody!!

possibly a small air leak somewhere between the carburetor and cylinder head. A plugged idle jet/ air bleed can also cause an engine to "Hunt", but generally will not cause it to die.

Thats the air bleed I was talking about. This bleeds air to mix in the nozzle and can cause the surging / hunting, but generally will not cause the engine to die. Glad it's working good for you now.

You have a fuel restriction which means you may have a non-venting fuel cap or you need to clean the carb, I am not familar with your engine so I can't tell you what carb kit to install, however try loosening the fuel cap to see if it helps. Have a good one. Geo

First response called it!

pikeslayer: There's a fuel screen screwed into the outlet fitting of the fuel tank - standard issue for most Honda applications.
paul

Thats the air bleed I was talking about. This bleeds air to mix in the nozzle and can cause the surging / hunting, but generally will not cause the engine to die. Glad it's working good for you now.

It's an air bleed? This little hole is in the bottom of the plastic jobby. It looks as if it leads down to the bowl. There is another hole about 1/16" that appears to lead to the air filter and the other way to in front of the throttle plate. Wouldn't this 1/16th" hole be the air bleed?

First response called it!

pikeslayer: There's a fuel screen screwed into the outlet fitting of the fuel tank - standard issue for most Honda applications.
paul


I'll give you credit for calling it, but that's a little vague, "fuel restriction". Are you suggesting the fuel screen is clogged, or their is a hole in it?

It's an air bleed? This little hole is in the bottom of the plastic jobby. It looks as if it leads down to the bowl. There is another hole about 1/16" that appears to lead to the air filter and the other way to in front of the throttle plate. Wouldn't this 1/16th" hole be the air bleed?

On some carburetors that same hole vents the fuel bowl as well as fees air into the air bleed circuit, it's metered through the pilot jet.

It's an air bleed? This little hole is in the bottom of the plastic jobby. It looks as if it leads down to the bowl. There is another hole about 1/16" that appears to lead to the air filter and the other way to in front of the throttle plate. Wouldn't this 1/16th" hole be the air bleed?

Plastic jobby? Hmm, I'll have to look that definition up, as I'm not familiar with it LOL.
A fuel supply restriction is a just that - a restriction, finding it is the hard part sometimes. Be it tank, line or carb. Was just giving credit where credit is due.

Thought I'd post an update. Snow blower has been running fine. It was that tiny hole in the pilot jet (I think). Thanks for all your help, this is a great forum.