My old Big Bear runs and cuts out and burns rich no matter what you do to it. New plug, cleaned carb, rebuilt carb, adjusted valves, new air filter, new float. Got to be fuel related??? The only time the motor sounds like it is going to run right is when I shut the gas off and let it run out of gas. When I do this and when the fuel bowl is running out of gas the motor will scream. Any thoughts? Thanks very much.

 

If it's running too rich then it could be getting too much gas or not getting enough air, or both. The way to get too much gas is the wrong size jet (or somebody drilled it out) or the needle is raised too high. You might could adjust the air screw to let it get more air. I would verify the jets are correct, make sure the needle is set right, and make sure the air screw is adjusted correctly. You could always drop the needle to see if it helps, it won't cost anything.

 

Why would the motor speed up when I let the carb run dry. It will scream when I do this. Could a float adjustment be an issue also? Could the float be letting too much gas into the bowl and flooding the carb? The jet is stock. I will check the needle to see what notch it is in. The pilot jet screw is the only adjustment screw on the carb. Is that the one you are referring to? Thanks

 

The engine screams when you let it run out of fuel because that causes the engine to run lean (starving for fuel; too much air for the amount of fuel). The float height could be a problem, if it's too rich then the float height could be too high.

 

im having the same problem with my ytm200 got it narrowd down to the pilot jet, i adjusted my float 20+ times to the point it wouldnt let any gas into the carb. id agree with it being your pilot jet or choke stuck open, pretty sure the stock pilot is 42.5