You have to pull the jet and rod it out with something soft. Stranded copper wire works well. There will be hard deposits from the ethanol that 'tune-up-in-a-can' will not touch. Should run fine after that, although new deposits will re-form quicker now.
Snow Equipment Owning/Operating Snowblower won't idle
- Thread starter BackwoodsMan
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BackwoodsMan
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I am making progress. There was a jet I missed in my first cleaning. This Yamaha carb is different than the ones I saw on the YouTube videos. It has a 2 inch long tube that threads in the bottom of the carb and is not part of the bowl bolt. After I cleaned that long tube, it idled just fine. I included a picture in case someone else has this model.
I still have a problem with lunging at full throttle. It seems like the engine stumbles and the governor opens the throttle. If I go to half choke it runs OK. I cleaned the main (center jet) so I am not sure it is a fuel issue. I will clean the plug next.
I still have a problem with lunging at full throttle. It seems like the engine stumbles and the governor opens the throttle. If I go to half choke it runs OK. I cleaned the main (center jet) so I am not sure it is a fuel issue. I will clean the plug next.
Sounds to me like there is still a blockage somewhere. When it runs okay with partial choke, that pretty much tells me it's starving for fuel. I'd remove the carb and take it all apart and clean it again, then blow out all the passages and the parts. Spraying the carb with carb cleaner loosens the dirt, but you need to move it out of there with air pressure, otherwise it will just find another place to rest. Remove the float and needle valve (no air pressure on the float tho) spray the float with cleaner (unless it's cork, which it does not appear to be) and just let it air-dry on it's own, wipe down the needle valve with a clean shop towel, then blow it off using your breath. You could use air pressure, but chances are it's gonna blow out of your hand and you'll never find it. There's no reason to remove the needle's "seat", but air blow that too. Be very careful not to disturb the float setting-tab or you'll need to re-adjust that height.
In your picture, it's hard to tell if the carb body (inboard of the "O" ring) is dirty or it's just stained. If its dirt, get rid of it - it will eventually cause problems. That tower looking thingy (technical term) between the float looks dirty too, clean that as well. Take your time, you're getting there.
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The Fred
Veteran Member
I can't see a breakdown of your carb online but I can tell you that Japanese carbs have some very tiny orifices for the low speed circuit. Like everyone says you DO have a partially plugged jet somewhere. Look CLOSELY inside the carb body with the butterfly shut. Now look for transitional ports that the butterfly just passes by when you just crack the throttle past idle. Follow the holes(s) down to the respective jet. Once you find this tiny orifice you will find a way to clean it and trouble be gone.
Beware some of these Japanese carbs use plastic jets and damage very easily. I can tell by your nice photo that there has definitely been water in the carb fuel bowl and corrosion has set in somewhere. You can pick up a set of 300 magnifying (reading) glasses at Walmart for a few bucks and with a bright flashlight you can really see these tiny jets and the plugging.
Good luck you'll find the problem.
Side note: most newer small engine carburetors, weed whackers, chainsaws have the tiniest jets for emissions that it is cheaper to replace then to try to fix. These carbs are designed to be thrown away. Planned obsolescence I think it is called. It has little to do with ethanol but with the manufacturer wanting you to buy new equipment much sooner than you are used to. Same with wash machines and dryers.
Fred
Beware some of these Japanese carbs use plastic jets and damage very easily. I can tell by your nice photo that there has definitely been water in the carb fuel bowl and corrosion has set in somewhere. You can pick up a set of 300 magnifying (reading) glasses at Walmart for a few bucks and with a bright flashlight you can really see these tiny jets and the plugging.
Good luck you'll find the problem.
Side note: most newer small engine carburetors, weed whackers, chainsaws have the tiniest jets for emissions that it is cheaper to replace then to try to fix. These carbs are designed to be thrown away. Planned obsolescence I think it is called. It has little to do with ethanol but with the manufacturer wanting you to buy new equipment much sooner than you are used to. Same with wash machines and dryers.
Fred
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BackwoodsMan
New member
I am still working on the lunging problem at full throttle. I did a thorough cleaning of the carb and made sure every port was open. I pushed a small drill through the main jet to insure it is fully open. The engine idles perfectly, but at full throttle it will lung every 5 seconds. I can see the governor pull the throttle wide open and a big spray of fuel shoots up into the throat. Some droplets even come out the air intake side. The engine then runs OK for 5 seconds and the cycle is repeated. if I move the choke to half set, the lunging stops. I am about ready to replace the carb, but I can't imagine what would be different with a new carb.
