I have a 2000 Yamaha 8 hp 2 stoke. It is running lean. It idles fine then when I increase the throtle the motor cuts out. I first cleaned out the carb and rebuild it. I also replaced the fuel hose, and the symtoms still remain. When I pull the choke out the motor works better temporarly. Is the float need adjustment? I would welcome any suggestions. Dave
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RE: Yamaha
Your problem is in the carb. The off-idle circuit is the problem. Most likely you have some dirt or sludge in the small channels of the body of the carb. Drop it in cleaning solvent after dismantling and then blow out all the passages with compressed air
Your problem is in the carb. The off-idle circuit is the problem. Most likely you have some dirt or sludge in the small channels of the body of the carb. Drop it in cleaning solvent after dismantling and then blow out all the passages with compressed air
vent
Could be a plugged vent hole in your tank.Before taking the carb off again,I would loosen the gas cap to see if it makes a difference.Check for a kink in your fuel line.Hope it's a easy fix.
Could be a plugged vent hole in your tank.Before taking the carb off again,I would loosen the gas cap to see if it makes a difference.Check for a kink in your fuel line.Hope it's a easy fix.
Dave, my 8hp Yamaha was stolen before it ever
had a defect so I never tore into it. BUT, all carbs are the same. Sounds like you know that. I also suspect, you know about venting. Now, that said, when you tore down your carb, did you identify the mid-range passage and air bleed? It is often hidden by a rubber plug over and next to the main jet. Once you find it, mechanical cleaning (reaming and poking) might be called for. Or you could ship it to me. I'll fix it for free.
had a defect so I never tore into it. BUT, all carbs are the same. Sounds like you know that. I also suspect, you know about venting. Now, that said, when you tore down your carb, did you identify the mid-range passage and air bleed? It is often hidden by a rubber plug over and next to the main jet. Once you find it, mechanical cleaning (reaming and poking) might be called for. Or you could ship it to me. I'll fix it for free.
carb frustation
Thanks, but I am even more confused now, I tore the whole carb apart, cleaned all jets and let it soak in solvent. It was spotless, then I took apart the fuel pump, it was spotless, then I replasced the fuel filter, it was clean, then I replaced the gas line thinking there might be a air gap somewhere, None of these things have solved the problem. Any more ideas? I am out? Thanks Dave
Thanks, but I am even more confused now, I tore the whole carb apart, cleaned all jets and let it soak in solvent. It was spotless, then I took apart the fuel pump, it was spotless, then I replasced the fuel filter, it was clean, then I replaced the gas line thinking there might be a air gap somewhere, None of these things have solved the problem. Any more ideas? I am out? Thanks Dave
Dave, do what Alan said, use compressed air
You also could use an aerosol spray can of carb cleaner such as Gumout, made by Penzoil. It has a red plastic tube with the can, that is used to direct the flow into small passages. You must insure the passages are clear with that test. Soaking won't tell you what you need to know. When you blow in a passageway, it must come out someplace else or it won't run. Can't say that enough.
You also could use an aerosol spray can of carb cleaner such as Gumout, made by Penzoil. It has a red plastic tube with the can, that is used to direct the flow into small passages. You must insure the passages are clear with that test. Soaking won't tell you what you need to know. When you blow in a passageway, it must come out someplace else or it won't run. Can't say that enough.
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