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Post by coachhejl on Dec 21, 2022 16:44:17 GMT -5
Just picked up a scooter and the carb fuel/air screw is plugged up. The acceleration is not good at all. It goes but seems like it slightly tries to bog sometimes on acceleration. Top end is smooth and feels correct. Surely I'll need access to an adjustable mix screw right? I watched a video and a $25 Amazon carb livened up a 50cc tao tao. I was thinking on starting with this. youtu.be/ogJd433pGm4Any opinions?
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Post by aeroxbud on Dec 22, 2022 5:13:51 GMT -5
You can usually drill out the plug that blocks the adjustment on the mixture screw.
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Post by Zino on Dec 22, 2022 8:22:05 GMT -5
if your scoot is unmodded the stock carb with stock jets is a good baseline for performance The engineers typically set them for a safe tune so that scoot dont blow up first, best gas mileage second and peak performance third.
For adjusting the carb you also can just buy 1 size smaller and larger pilot jet and take the one that runs best .
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Post by GrumpyUnk on Dec 22, 2022 10:03:17 GMT -5
Have you checked that the accelerator pump is functional? The brass looking vertical shaft on the back side of the carb leading downward to a bulge is the accelerator pump. It squirts a dash of fuel into the air intake when you open the throttle. If dysfunctional, you will get a bog when you open the throttle sort of quickly. You can look down the intake towards the throttle plate, ope the throttle twist grip, and you should see a squirt of fuel come out of a tube sticking into the air intake from about the 4:00 o'clock position. If not, fix the accelerator pump and it should improve. tom
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Post by coachhejl on Dec 22, 2022 10:23:03 GMT -5
Is that the mechanical thing that moves when the throttle cable is used? When I had the carb pulled apart, that squishy thing was mashed and gas was pumped up but they was when I had the bowl loose. Anyways I pulled the card last night and cleaned the heck out of everything. It didn't look dirty. Ran it this morning...same issue. About 1/2 to full it just sits there for a minute and then slowly goes faster. Rpms stay pretty low. Could it be too small of a main jet? Have you checked that the accelerator pump is functional? The brass looking vertical shaft on the back side of the carb leading downward to a bulge is the accelerator pump. It squirts a dash of fuel into the air intake when you open the throttle. If dysfunctional, you will get a bog when you open the throttle sort of quickly. You can look down the intake towards the throttle plate, ope the throttle twist grip, and you should see a squirt of fuel come out of a tube sticking into the air intake from about the 4:00 o'clock position. If not, fix the accelerator pump and it should improve. tom
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Post by 90GTVert on Dec 22, 2022 12:48:30 GMT -5
I replaced the sealed carb on my TaoTao because of the non-adjustable needle. I unsealed the mix screw and replaced the bowl screws, but that still left me with rich stutter when throttle was applied at times and a needle with no adjustment. Mine did not get significantly faster, but it did improve drivability.
I always suggest having a jet kit and going through a tuning process for the main jet.
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Post by coachhejl on Dec 22, 2022 14:14:29 GMT -5
1. I really appreciate you taking the time to answer my questions. I also found a no adjustable needle, as well as the fuel to air mix screw plugged. I have ordered another carb. The motor runs "well". Sounds healthy. It's just the bogging on acceleration...if I twist throttle more than about 1/2 or more at start. If I ease into it it would be fine. Does this sound like it's lean? Like being able to mix screw and/or adjust needle would help? Typically where would you put the snap washer to help this situation on the needle? Thanks again. I replaced the sealed carb on my TaoTao because of the non-adjustable needle. I unsealed the mix screw and replaced the bowl screws, but that still left me with rich stutter when throttle was applied at times and a needle with no adjustment. Mine did not get significantly faster, but it did improve drivability. I always suggest having a jet kit and going through a tuning process for the main jet.
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Post by 90GTVert on Dec 22, 2022 15:02:03 GMT -5
Sounds like it's lean somewhere or the accelerator pump isn't working. You'd put a shim under the needle clip if you wanted to try to richen it.
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Post by coachhejl on Dec 22, 2022 15:15:54 GMT -5
So raising the needle allows more fuel or air through? Sounds like it's lean somewhere or the accelerator pump isn't working. You'd put a shim under the needle clip if you wanted to try to richen it.
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Post by 90GTVert on Dec 22, 2022 17:12:32 GMT -5
Raising the needle lets more fuel in. The needle goes through a passage. The needle tapers from smaller at the bottom to larger at the top. As it rises it blocks less and less flow.
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