Did this problem come on suddenly or did it build up slowly? Did you check compression?
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Suddenly, and got slowly worse, havenât tried compression with a tester, just that it feels strong when pulling the cord, and no excessive blow-by.
If i shut the fuel, it runs perfect just before fuel in bowl runs out.
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Goran, black smoke means too much fuel, otherwise I have not repaired such a Honda engine yet, but with all similar engines, the most important thing is the preparation of the mixing mixture for part loads and idling. For this, the carburettor has very small holes, which are located next to the throttle valve, in many cases, the mixture is adjusted here by supplying fuel pre-mixed with air through the system to these nozzles, to open the air channel with the adjusting screw. A rich mixture - black smoke, coughing, poor strength,âŠ
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Exactly Tone, it must be running rich, all symptoms indicates that.
Even sparkplug was sooty black.
What i canât understand is that carburetor seems perfect, and the air/fuel mix needle iâve checked, and adjust to basic setting, and adjusted from that, no response at all.
I had a riding lawnmower acting this way before, in that case it was the float leaking (full of fuel) i didnât noticed that until i held the float in my hand, and felt the weight.
This Honda engine has a casted float, with some kind of âfoamâ inside, so thats not the culprit.
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Goran it does sound like a carb problem then. The carb on my GX340 was so bad both butterfly valves were so corroded they wouldnât move. I freed one, but the other broke. Rather than try any repair I just bought a new carb form AliExpress for $13.25 USD + $2.51 shipping.
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Hi Goran these have solid-state ignitions with windings and a special transistors built within the coil pac.
You need to test for ignition spark strength:
My handy-dandy ignition strength tester says for Small Engines the spark in open air must jump a 5 mm gap with strength:
As seen you can easily make up something similar for testing.
Tested weak spark the only adjustment is the coil to flywheel air gap. If O.K. time to change out the coil pac. Likely shorted coil windings or a leaking transistor.
To verify that that plastic float has not gone gasoline absorbed heavy it is easy.
Allow the float boat to fill as normal. True OFF the gasoline supply. Start and run the engine.
IF as the bowl fuel is used up the engine then starts to run normal, that float is too heavy, overfilling.
A good carb set up doing this will run normal then go leaner and leaner misfiring until the engine dies.
What Tone was trying to describe would be tiny side orifices into the main jet to allow air-bleed in for pre-air and fuel âemulsifcationâ blending. Air-fuel foamed, has a lower density and makes for more rapid mixing with air flow demand changes. The main jet can be clear. But the side air bleed orifices clogged. Usually causes a lean condition though.
Regards
Steve Unruh
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I like your viewpoint on life exspectency , my dad had a goooood heart and died on cancer, though he still lived untill 83.5 years-he had melinoma skin cancer for about 8 years-though he still stayed active untill his last few months or last year. And dont worry be happy life style i think is the best choice.
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I wouldnât be so sure. they had to get foam in somehow. 
Does that have both an idle and a throttle carb adjustment?
Did you tip it over and have oil run into the cylinder and it is still working its way out?
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Goran, here is the link,⊠look at pages 80 to 90,âŠ
here is another document from the Lombardini engine, I am attaching this link because there are very nice pictures so you can understand the principle of operation (pages 13 and 14)
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We were out picking up the nets, when Johan and JO had left, we got a few perches and a little pike.
I have smoked these, the pike got the neighbor, but I still have most of the perches.
Do you have any tips on how I can do this?
The wife isnât that interested in fish.
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Hi SteveU, very good suggestions, thanks.
I had tested the spark already, (with a good plug, with bent side electrode, 7mm, i have spark testers also) good, âfatâ spark.
I had the feeling these engines had âelectronicâ ignition, but iâve had engines with similar symptoms, where points gap was next to nothing.
As for the carb, it has the emulsion nozzle/jet like Tone mention, âside low-power channelâ iâve checked it, and adjusted the needle valve, no response.
Now for the float: it behaves exactly like you say when i shut the fuel, which i also consider as too high float level.
When i tinkered with floats like this before, they was made of something âclosed cellâ, like synthetic cork, impossible to soak?
But maybe im wrong? Im going to look after another carb, i have some, somewhere, or if the float is same size in the smaller, 5hp, carb?
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Hi Sean, no, no tip over.
It has to be the float, im going to look for a spare one today 
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Thank you Tone, going to check it out.
Soon itâs less work to build a gasifier for it, and throw the carb in the well 
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I feel that way about carbs in general. They are finicky devices with tiny passageways and orifices that can get clogged. Then there are the gaskets, valves, floats and diaphragms that can age and degrade performance. I have found I can often get a new carb for just a little more than the cost of a rebuild kit. No work needed and it is shiny new - no scrubbing and washing needed. So far I have replaced a chainsaw, cement mixer and now the generator carbs. Usually I prefer to repair rather than replace, but for carbs I make an exception. 
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Hi All,
Craig Kirkman, TheRepairSpecialists give some of the best understandable, illustrated how-does-it-work for small engines explanations Iâve ever seen:
He also does great on both 2-stroke and 4-stroke small engine carburetors.
To just replace with new is nice so long as those boats and cargo planes keep coming from China. Think COVID shutdowns and lockdowns. But think more political-economic in long low level conflict.
NOT understanding Make-Do, some day will have you stuck with your pants down around your ankles unable to run.
So, sure. Iâve been forced to buy new and just replace out, when they stop supplying replacement parts. Pulsator diaphragms, flow needles and seat, floats are pretty individual specific.
The time to learn modifying adapting; scrape, scrape cleaning up, is before you have too.
Hell of a lot more relevant than the guys actually making tiny model ships in a bottle. Gee-wizz look at my drone that I made. Lookie at my neat little dancing bear video that I programmed. How long of burn-out strip I can make.
Hand these fellows an old set aside IC engine and say make this run dude. Make this back to working capable. You no eat until you can. You no get to sleep in the house with lights and heat until you do.
Steve Unruh
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Probably not an issue in Sweden but if you are using gas with ethanol in it, you have to get the carb drained before storage. I have had small engine carbs that still had gas in the float bowl after the tank was emptied and engine run out of gas. Pull the bowl off and there are little green crystals in there and they must be scraped so if they get into a jet or other passage I think the carb is toast. Iâm agreeing with Marty. They are cheap and you can use your time better by just replacing them.
Iâm wondering , with the advent of fuel injection who still owns a set of jet drills?
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Hi Tom, that is an BIG issue in Sweden, not only there are a Lot of ethanol in the gasoline, there is also water (ethanol sucks up water from the air) there seems the stuff distilled away during refining are whats imported to Sweden, it really corrodes everything, even brass, all my âcollectionâ engines, and season engines run on alkylate fuel (atleast the last fill up before storage) well, expensive fuel, but a lot cheaper than new carbs, kits, and diaphragms.
Well, there are âblankâ gasoline available, without ethanol, more expensive, but even that attacks the carbâs leaving white crust that needs to be sand-blasted away.
Edit: im guilty to own a set of jet-drills
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What is specific about jet drills, are they not normal drills?
Where do you find blank gasoline?
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No JohanM.
They are not the same. They are more about insertion gauge size verifying. Somewhat able to clean and clear. Not removing metal and damaging.
Think as is in between torch jets cleaning burr-wires set, and a twist drills for solids metals holes making.
S.U.
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Aah, ok. So they are not actually drills, just to clean out deposits and such. Probably with a smooth surface on some of the rod to check size.
Gasoline that has been standing for many years for instance requires some cleaning.
Thank you Steve
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