Dongfang 150cc scooter problem
 

Hello. Just purchased a 150cc sunny sports dongoing scooter. It had been sitting for about 5 years. Had to fix various things on it, but now having a problem with it running. Changed gas, new gas filter, adjusted valves, new hose's ...now, it starts and idles fine, but as soon as you open the throttle, it starts to miss and die at anything over 2500 rpm. You can hold it wide open and it misses, and barely runs, let off the throttle and it returns to idle and runs just fine. I have cleaned the carb several times and cannot find anything to cause the problem. I am stumped. ..any suggestions on what to do next?

You have to properly adjust the mixture.

I bet you got you vacuum lines mixed up I know that is what I did and it took me a few weeks to get it right.

When you clean your carburetor, are you removing the jets....or just spraying something thru them? Is your air cleaner intact....and not plugged?

When all else fails, new parts for a gy6 are dirt cheap. A new 24mm carb can be had for less than $25, and shipped for free.

Once you get it sorted out, I'd suggest you start burning ethanol free gas, and maybe add a little bit of carb/injector cleaner occasionally. Don't leave the scooter setting for extended periods with gas in the carb....pull the screw in the end of the hose and let the bowl drain. Do this and you will have no more carb problems.

Definitely a jet or mixture issue.

I have the same unit can you take a picture of you vacuum routing and post it I will bet it's wrong my did the same thing when hoses were mixed up.

Ok...ordered a brand new carb. Put it on and exactly the same thing. Omg. This is driving me insane. New o ring on the intake. ..all new hose's.
Possibly cdi, spark plug? ??? Again starts right up, idles great, will Rev to about 2500 and start to sputter and act like it wants to die. Put the throttle all the way and misses and hardly runs. ....one thing I did notice was the fuel pump does not fill the new filter all the way. .only about half way. Possibly it? ??

Ok, eliminated the fuel pump, spark plug and vacuum hose's.
So I'm now thinking electrical. Rev limiter? ??

I asked this before, but maybe you missed it......is your air box attached to your carb?

Yes, original air box

You do know the lever that hold the bike up keep the speed from going over a set speed right?

Seriously? ?? I will see if there is a switch on it, although it does the same thing running down the road.

No switch for Rev when is up on the stand. Checked air box...no help there. .I guess I'll buy a new cdi and coil

The switch is where the swing lock is if we are talking about the same bike I have with 2 front wheels

Are you talking about the switch that tells you that the suspension is opened up? Yes I have the trike with two wheels up front.