Posted: 11/3/2013 4:28:28 PM EDT
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Namely, a Yamaha inverter generator (EF2400is), that has a surging idle issue (vroOM, vroOM ...), but runs well under load. I have changed the plug, and sprayed carb cleaner through it, and ran a couple tanks of injector cleaner through the gas. No help.
What sucks, is that there are no local Yamaha service locations. So  to Yamaha on that.
My question, if I buy a $60 Yamaha service manual, do you think it will explain how to clean the carburetor, and how to adjust it afterwards? Any other ideas welcome. It's about 6 years old, and I really like it when it's running well. Thanks. |
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Low speed jet is clogged. The carburetor is simple, it just has goo in the passages. While the manual may help, it really is a common sense skillset one gets from rebuilding a few small engine carbs. But a rote novice could do this as long as good notes are taken. And pictures. |
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Quoted:
Low speed jet is clogged. The carburetor is simple, it just has goo in the passages. While the manual may help, it really is a common sense skillset one gets from rebuilding a few small engine carbs. But a rote novice could do this as long as good notes are taken. And pictures. Thanks, but my main concern is adjusting the carburetor after i put it back together. Or, am I over thinking this? |
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Don't touch the adjustment screws, or at least count the number of turns in to the stop and set them at the same number after reassembly. carbs on those are simple, and like Keith said the low speed jet and passages are clogged. After you get it running add some fuel stabilizer to avoid this in the future. |
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If you have any mechanical aptitude you can probably pull this off. A schematic will certainly help. Most likely the place you buy the rebuild kit from will have one online for free.
The air/fuel screw and idle screw are the critical ones. Count the number of turns when you remove them and write it down. Set the new ones the same way. The rest is just replacing old parts with new. Any small engine shop in your area could handle this no problem. Or bring the generator, carbs kit and a bottle of bourbon to Waco and get it done for free. |
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Before you rip the carb off the engine. Look at the output from the fuel tank. There is probably a filter either right there or a needle filter inside the fuel line. I had a honda surging and probably cleaned the carb a half dozen times before finding the filter clogged. FYI, Jap carbs are a thing of beauty to work on compared to US made ones.
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Quoted: If you have any mechanical aptitude you can probably pull this off. A schematic will certainly help. Most likely the place you buy the rebuild kit from will have one online for free. The air/fuel screw and idle screw are the critical ones. Count the number of turns when you remove them and write it down. Set the new ones the same way. The rest is just replacing old parts with new. Any small engine shop in your area could handle this no problem. Or bring the generator, carbs kit and a bottle of bourbon to Waco and get it done for free. That is the key. If you know the location of this screw, count the turns to bottom (righty-tighty) the screw, then remove it and give it a few shots of Berryman B12 carb cleaner from the spray can. Use the wand but ALWAYS wear goggles, this solvent will BURN. Replace the screw fully tight, then back it out the same number of turns. Some carbs have limit caps on the idle mixture adjustment...these usually can be defeated but be careful you document the number of turns in any case. |
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Does this happen with the idle switch set to "Auto"? As in, when it idles at really low speed, does it seem like it's about to sputter and die only for the revs to kick back up to keep the engine running? Something similar happened to me on my inverter generator. It seems like the issue was solved when I changed oil. I think I used a cheap 10W-30 or maybe even a straight 30W oil to break it in. I changed the oil with Mobil 1 10W-30 (it calls for that weight oil), made sure it's up to the correct level, and it's been running smooth ever since. Weird. I also had a leaking fuel filter that I replaced, but I think the idle issue was fixed before that. |
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Quoted: Thanks guys. I'll give it a shot tomorrow evening. I have a parts list with exploded diagrams, which are pretty detailed. |
As already said that surge is typical of a gunked up idle circuit. Before you go pulling the carb out try this trick. From the looks of that video that carb looks super easy to access and get out. I would not buy a manual, there is enough knowledge here to help you along. |
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One other thing to check is the carb spacer. On my lawn mower there is a plastic spacer between the barb body and the intake. Mine had a crack in it and it would surge like you are describing. A low speed jet or passage that is completely clogged will prevent the engine from idling- it will just die. A partial clog might cause it to surge. Make sure the air filter is clean and not rotting. The first and easiest thing to try is to drain the fuel and put fresh fuel in. When gas sits for a long time it will turn into something like varnish, and it is a bitch to clean out unless you can vat the carb. I used to work on Honda motorcycles, and Yamahas, and my dad was a Honda mechanic starting in about '65. We both would see bikes that had sat all winter come in because they wouldn't run. The gas would go bad and plug the small passages. After you get it running use fuel stabilizer, turn off the petcock and drain the carb when letting it sit. That will eliminate a lot of headaches. |
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Quoted: As already said that surge is typical of a gunked up idle circuit. Before you go pulling the carb out try this trick. From the looks of that video that carb looks super easy to access and get out. I would not buy a manual, there is enough knowledge here to help you along. Weird. Just some spray of carb cleaner. That's different from my issue. There was more time between surges and the surges were more pronounced. |
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Quoted:
Exactly. Good advice. Quoted:
Quoted:
Don't count the turns of the screw/s out, count them in until the needle GENTLY seats. Then remove it, do your cleaning, run the needle back in until it seats gently and back it out the correct amount of turns. Exactly. Good advice. Duly noted. Thanks. |
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Quoted: That is the key. If you know the location of this screw, count the turns to bottom (righty-tighty) the screw, then remove it and give it a few shots of Berryman B12 carb cleaner from the spray can. Use the wand but ALWAYS wear goggles, this solvent will BURN. Replace the screw fully tight, then back it out the same number of turns. Some carbs have limit caps on the idle mixture adjustment...these usually can be defeated but be careful you document the number of turns in any case. Yeah, there is nothing like a shot of Berryman to the eye! After you get past the inital Oh Shit and freakout stage and think you just successfully blinded yourself for several minutes everything goes back to normal. Not pleasant and you sure don't want to happen again. Kinda freaky to think that stuff ruins or melts paint, plastic, rubber, and a bunch of other stuff after you get it in your eye!  |
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Quoted:
As already said that surge is typical of a gunked up idle circuit. Before you go pulling the carb out try this trick.  http://youtu.be/KjLf_tQi0zY
From the looks of that video that carb looks super easy to access and get out. I would not buy a manual, there is enough knowledge here to help you along. Already saw that vid, and tried it a few times. I might have some insoluble stuff in there, I guess. |
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Does this happen with the idle switch set to "Auto"? As in, when it idles at really low speed, does it seem like it's about to sputter and die only for the revs to kick back up to keep the engine running? Something similar happened to me on my inverter generator. It seems like the issue was solved when I changed oil. I think I used a cheap 10W-30 or maybe even a straight 30W oil to break it in. I changed the oil with Mobil 1 10W-30 (it calls for that weight oil), made sure it's up to the correct level, and it's been running smooth ever since. Weird. I also had a leaking fuel filter that I replaced, but I think the idle issue was fixed before that. Well, it seems to keep running OK, and usually takes a load when it is plugged in (1500 Watt heater). But, it will kick the overload light on sometimes, which shuts off the output until restarted. I did do an oil change, just some Walmart 10W-30. Might put some better lube in there. |
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Yeah, there is nothing like a shot of Berryman to the eye! After you get past the inital Oh Shit and freakout stage and think you just successfully blinded yourself for several minutes everything goes back to normal. Not pleasant and you sure don't want to happen again. Kinda freaky to think that stuff ruins or melts paint, plastic, rubber, and a bunch of other stuff after you get it in your eye!
Quoted:
Quoted:
That is the key. If you know the location of this screw, count the turns to bottom (righty-tighty) the screw, then remove it and give it a few shots of Berryman B12 carb cleaner from the spray can. Use the wand but ALWAYS wear goggles, this solvent will BURN. Replace the screw fully tight, then back it out the same number of turns. Some carbs have limit caps on the idle mixture adjustment...these usually can be defeated but be careful you document the number of turns in any case. Yeah, there is nothing like a shot of Berryman to the eye! After you get past the inital Oh Shit and freakout stage and think you just successfully blinded yourself for several minutes everything goes back to normal. Not pleasant and you sure don't want to happen again. Kinda freaky to think that stuff ruins or melts paint, plastic, rubber, and a bunch of other stuff after you get it in your eye!
Yup I had this happen to me. I was trying to blindly walk quickly up to the hose on the back of the house to run water in my eyes. Very scary. And yes I immediately went and put the glasses on to finish. |
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Quoted: Well, it seems to keep running OK, and usually takes a load when it is plugged in (1500 Watt heater). But, it will kick the overload light on sometimes, which shuts off the output until restarted. I did do an oil change, just some Walmart 10W-30. Might put some better lube in there. Quoted: Quoted: Does this happen with the idle switch set to "Auto"? As in, when it idles at really low speed, does it seem like it's about to sputter and die only for the revs to kick back up to keep the engine running? Something similar happened to me on my inverter generator. It seems like the issue was solved when I changed oil. I think I used a cheap 10W-30 or maybe even a straight 30W oil to break it in. I changed the oil with Mobil 1 10W-30 (it calls for that weight oil), made sure it's up to the correct level, and it's been running smooth ever since. Weird. I also had a leaking fuel filter that I replaced, but I think the idle issue was fixed before that. Well, it seems to keep running OK, and usually takes a load when it is plugged in (1500 Watt heater). But, it will kick the overload light on sometimes, which shuts off the output until restarted. I did do an oil change, just some Walmart 10W-30. Might put some better lube in there. After seeing your video, I doubt that's the problem. I actually don't have any logical explanation for why it fixed mine either but I figured I'd pass it on. |
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Don't touch the adjustment screws, or at least count the number of turns in to the stop and set them at the same number after reassembly. carbs on those are simple, and like Keith said the low speed jet and passages are clogged. After you get it running add some fuel stabilizer to avoid this in the future. Don't you have to remove the screws to clean the low speed jet & passages? |
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As already said that surge is typical of a gunked up idle circuit. Before you go pulling the carb out try this trick. http://youtu.be/KjLf_tQi0zY
From the looks of that video that carb looks super easy to access and get out. I would not buy a manual, there is enough knowledge here to help you along. Good post. He made sure we could see exactly where to shoot the carb cleaner. I switched over to youtube just to hit " Like ". He's got over 12K hits and only 15 likes ( with mine ). eta: There's a shitload more info in the youtube comment section. |
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Don't you have to remove the screws to clean the low speed jet & passages? Quoted:
Quoted:
Don't touch the adjustment screws, or at least count the number of turns in to the stop and set them at the same number after reassembly. carbs on those are simple, and like Keith said the low speed jet and passages are clogged. After you get it running add some fuel stabilizer to avoid this in the future. Don't you have to remove the screws to clean the low speed jet & passages? It depends on how badly the carb is gunked up. I posted that before my brain kicked in. All that is necessary is to count the turns in, then remove the screw. After cleaning run it in then back it out the same number of turns. I would bet that it is a turn and a half. |