Carburetor (150cc scooter) difficulties!? By phil1039 (Read 987 times)

[phil1039]

My scooter has been having trouble at about quarter throttle(it has a miss, then runs fine when the main jet {I assume main jet} kicks in. I tried adjusting the air/fuel screw (was factory set at three turns out). But now no matter where I put the air/fuel screw the scooter will not idle, it just turns off. I've set the idle screw all the way up and that seems to keep it on, but the rear tire just spins by its self at a high speed. And if i turn the idle down, the scooter shuts off. Here is the bottom line; the scooter will not idle smoothly at any position of the air/fuel screw. ALSO I have checked the air/fuel screw and it is not damaged, and their is no vaccum leaks as far as I know.

[Alleyoop]

It appears your PILOT JET and PASSAGE are clogged if turning the Fuel Ratio Screw in either direction does not do anything.
So take the carb off and Take the PILOT JET out and clean it. You must be able to see daylight through it.

Get a Can of Spray Carb cleaner they come with a thin straw WITH THE JET still out stick the straw in the hole and SPRAY just come out here by the tiny holes by the butterfly.

You then adjust the mixture to get the HIGHEST IDLE from the fuel mixture screw. Then you lower the idle using the IDLE SPEED screw so that your rear wheel just barely wants to turn.
Alleyoop




When spraying into the Pilot Jet passage Spray should come out here:

[phil1039]

The bottom of the carb has cut off screws so I have no way of getting to it. I tried to just spray it real good with carb cleaner but that didn't seem to help. Now when I ride the scooter If the idle is turned high the scooter wants to take off; and if the idle is turned down low, it dies.

[toxictom]

Can you try to use a dremel or hacksaw blade to cut shallow slots in the screws? If you can get them out you can replace them with ones with a regular head on them. I agree that it is likely a little piece of crud in the jets.

[rob63]

Jul 2, 2013 7:50:54 GMT -6 phil1039 said:

The bottom of the carb has cut off screws so I have no way of getting to it. I tried to just spray it real good with carb cleaner but that didn't seem to help. Now when I ride the scooter If the idle is turned high the scooter wants to take off; and if the idle is turned down low, it dies.

To save faffing around I`d buy a new carb, they`re cheap enough. At least you`ll know that it should be in fairly good shape, and have proper screws which you can remove in order to clean inside.

[tgunnz2002]

I use guitar strings to clean the jets. they are small enough. the pilot jet is definitely the problem