Carburetor Help. By hellspigeon (Read 560 times)

[hellspigeon]

I took the Mikuni carb off my 150 scooter to clean it. After looking at it for a moment, I realized that there is an open nipple to the left of the fuel inlet nipple and just below the screw that holds the choke lever in. It wasn't plugged into anything when I bought it, and it never occurred to me to do anything about it until now. I have no idea what it's for. What I do know is that it goes straight down towards the float bowl and stops at the very top of it. I would appreciate it if anyone can tell me what this nipple is for, and how to properly set it up. It's just been sitting there like a freely open nipple into the float bowl. Msg me if you need more photos.

[DrRocco]

If I'm tracking you correctly, that's the drain to the bowl in your carb. On my scoot, it's attached to a spring-covered hose which is open and pointing to the pavement below.

[Alleyoop]

That is the overflow and vent to the carb bowl, if the float does not shut off the fuel for some reason fuel will come pouring out of that nipple. The CVK carbs has that vent on the other side of the carb but they do the same thing.
Here is a pic of one they usually have a 2" curved hose pointing down.
Alleyoop

[hellspigeon]

Thanks for the help guys; very informative. I cleaned out the carb, and the scooter came back to life. I let it sit for several hours; the scooter started up just fine again. I let it sit overnight, and in the morning the scooter wouldn't start up. So it's back to the drawing board for me.

[Alleyoop]

Did you try to adjust the carbs fuel ratio mixture? It appears it needs more fuel when cold.
Alleyoop

Here is your carb see that screw that is your Fuel Ratio mixture. Give it 1/2 turn to the LEFT and see if that helps the cold starts.

[Bashan]

Just cleaned carb and won't start the next day? Check the float valve. Also, as a homage to the immortal Sprocket, have you checked your valve gaps? He is watching.