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Honda GX340 needs half choke to run smooth

495man

495man

Well-known Member
Have a little 11 HP Honda GX340. Had it several years, done nothing to it but put gas in it (runs very little)

I run fuel stabilizer in it.

When I have the engine at wide open throttle, I have to leave the choke halfway on or the engine misses. Runs perfect on half choke.

I drained fuel, put new 91 octane fuel in it, new spark plug. Still does it?
 
Id like to think your main jet is half plugged. Located in the bottom of the carb, after you take the bowl off.
 
I have a water pump that does the same thing a couple of times a year.
Time to remove and clean out the carb.
 
while others on this board may disagree , try running some sea-foam though it. Seems to work a lot of times for me and its only $7 or $8 a can. Bill
 
I've run into that problem on several small engines. Check all the obvious first, vacuum leaks, valve lash,
fuel delivery, float level, and clean, clean, clean the carb jets.

As a last resort, a couple times I have had to drill the main jet as a last resort. It has to be surgically
done with minimal increments with special jet drills. Or if you can buy the next over jet, or "a" jet to
experiment with is better, then you can undo if you over do!
 
I have a Troy built generator here that I could get to run the same way and found that the gas the guy had used was the low prices stuff with alcohol in it and found the rubber gasket in the bottom to be bad due to the alcohol in the gas. Had to order a kit for the carb and not sure when the kit will get here. I took the float bowl off and poked out the main jet and then found I could make it run if choked. Pulled it open again and found the gasket did not fit in the groves like it should which it the whole problem
 
Inspect the fuel pump diaphragm, probably need to replace the fuel lines, clean the carb. Ethanol eats them all up and leaves debris in the carburetor.
 
Hello 495man,


You have plenty of fuel reaching the carburetor, that is why it runs on chocke. I
suspect you have a partially clogged high speed jet. I would also check the air filter,
bet you it needs a cleaning as well. If there are mixture screws you need to open up, (screw out), the high speed one at least 1/2 turn. There may be water in the bowl of the carb also,


Guido.
 
Thanks for bringing this up.
I have a wood splitter (TSC)with 11 HP B&S that does the same thing. The carb (Walbro LMT) is clean, main jet is clean and non adjustable. I am hesitant to open the main jet, as I would think they tested the engines for this application, but I have not come up with a better solution.
 
I work on small engines. That problem is common for engines not run enough. Gas gets old varnish builds clogs up the jets and passages. Time to clean
out the carb.
 

Thanks all.

Air filter is clean, does it even running with out air filter in place.

I'll see what I can do with the carb, I may try the seafoam type thing first, if no change I guess it is coming apart.
 

I believe that "young fella" Old has hit the nail right on the head. I have seen rubber parts swollen up as he described. Once you get it running again, the way to avoid re-occurrence is to use stabilizer, but also before storing, to shut the gas off, then run it until it has used the gas in the bowl and in the lines.
 
Take the carb apart and clean real well well. Use a thin tag wire to poke in all the passages. You may find green
sludge in the bottom of the float bowl. The center bolt maybe hollow and if so will have a tiny cross passage.
Use spray carb cleaner with a straw to blow out the passages. I set up a place to work where I can set down and
take my time. Lay out a big sheet of cardboard on top of the work bench to trap parts and some trays to soak 'em
in. Honda and Tecumseh carbs are pretty simple.
 

Ok, seems to work great now.

I put some seafoam in it as per directions, did that twice, smoothed out the miss at full throttle, but would still miss when load applied to engine.

I took carb apart, some sludge in bowl and jet, but not plugged or blocked. Cleaned that up and soaked jet in seafoam, reassembled, works perfect now.

Only issue was finding a slotted screw driver to fit inside the jet tower, but was big enough to turn jet. Ended up taking angle grinder to a bigger screw driver and made it fit....

Thanks for all the help.
 

More than likely the idle circuit with it's smaller passages is plugged. The idle circuit remains in play at full rom and full load supplying a significant potion of the fuel demand.
When shutting down small equipment . The tank valve is shut off and engine ran until it wheezes from insufficient fuel. The choke is 1/2 applied and then later fully applied to draw the carb's fuel bowl.
Last week I started a generator that had been sitting in storage for three years without snake oil being added to the fuel . Started right up and took a load no problem.
 
(quoted from post at 11:50:50 12/06/15)
More than likely the idle circuit with it's smaller passages is plugged. The idle circuit remains in play at full rom and full load supplying a significant potion of the fuel demand.
When shutting down small equipment . The tank valve is shut off and engine ran until it wheezes from insufficient fuel. The choke is 1/2 applied and then later fully applied to draw the carb's fuel bowl.
Last week I started a generator that had been sitting in storage for three years without snake oil being added to the fuel . Started right up and took a load no problem.
Click to expand...

I let it run dry this time, normally had no issues though, engine is 8 years old and has never been run dry and sits for months on end. Hope I don't have issues again and can just put gas in it, not snake oil.
 
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