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Discussion Starter #1
I just purchased a 07 sportsman 450 that is having carburetor issues. When I started going through the carb I found that the previous owner had glued a hardware bolt into a hole located on the right side as you can see in the image. I got the bolt out and it looks like it should be just a plugged hole to prevent unmetered air. Can anyone enlighten me on what this hole is like from the factory?

The issues it is having is that it bogs down about 1/4 throttle like it has a dead spot. After you throttle past that point its fine. Everything internal seems to be just fine.

Any imput is appreciated.
Thanks
 

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That was an undrilled unused port on the original carb - that carb appears to be a Chinese replacement. The carb in the pic has lugs on the float bowl that were intended for a mounting bracket - possibly for mounting the carb side by side with another.

The bolt is possibly plugging a vacuum port. If it is plugging a vacuum port, it's fine as long as it's sealed. If it is sealed, it's not the cause of your bog. The bog is caused by a lack of fuel being mixed with the incoming air. You might try raising the fuel level in the float bowl or raise the slide needle one notch. Enriching the idle fuel mixture a 1/4 turn on the pilot screw might help also. Running non-ethanol fuel or high octane fuel is a possible solution.
 

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Thanks scotiaboy and latebird.
It wasn't the throttle kill issue which is good to know more about. I plugged up the hole with silicon. I think the bogging issue was mostly because the air filter tube was off while I was troubleshooting preventing sufficient vacuum to lift the slider.
I got it running pretty good. I think I had to back the air fuel screw out more than needed so I will check the intake tube tomorrow.
After working with it it would drip fuel out of the bottom drain hose when I would rev it. I plugged the tube for know. The float isn't sticking or it would just be pouring fuel out.

Does anyone have any idea why it's dripping fuel under full throttle?
Thanks again
 

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Thanks scotiaboy and latebird.
It wasn't the throttle kill issue which is good to know more about. I plugged up the hole with silicon. I think the bogging issue was mostly because the air filter tube was off while I was troubleshooting preventing sufficient vacuum to lift the slider.
I got it running pretty good. I think I had to back the air fuel screw out more than needed so I will check the intake tube tomorrow.
After working with it it would drip fuel out of the bottom drain hose when I would rev it. I plugged the tube for know. The float isn't sticking or it would just be pouring fuel out.

Does anyone have any idea why it's dripping fuel under full throttle?
Thanks again
Silicone is not gas resistant and will soften and/or melt when exposed to gasoline - fill the hole with epoxy. Yes, it will bog if the air box is removed or if the air filter is removed from the air box. Setting the fuel screw out more than std. is normal when using alcohol blended fuel. DO NOT PLUG the drain hose. It will cause poor running at the least and can cause engine flooding. Worse case, with the drain hose plugged, fuel can fill the crankcase. I have seen Chinese carbs where the top of the overfull pipe in the float bowl was level with the surface of the float bowl. The normal fuel level is even with the surface of the float bowl, so vibration or sloshing of the fuel will cause spillage. Quality carbs typically have the top of the tube 1 -2 mm above the surface of the float bowl. Finally, when the throttle is wide open the vacuum is drawing on the fuel and will momentarily raise the fuel level in the bowl. Again, if the overflow pipe is even with the surface of the float bowl, an increase in fuel level will cause spillage.
 
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