Popping through the carb By rsw1158 (Read 1,183 times)

[Alleyoop]

From what you saying I think to much fuel is being fed when cold. I can make mind act that way with my MANUAL choke . ON days when it is not that cold If I RETRACT my Enricher all the way it will start up and idle low then if I extend it a little the rpms rise. It all depends on the temp and the amount of fuel it needs. But I do question that the Fuel Ratio Mixture does nothing when turned in either direction. If we could get the Fuel Ratio Mixture to cut off some fuel it would act like its supposed to.

How many turns is the Fuel Ratio screw out from the closed position?

Try this with the Fuel Ratio Screw but do this after it is warm. Turn the screw clockwise 1/4 at a time and see if it kills the motor.
Alleyoop

[rsw1158]

Right now I have it turned out 1 3/4 turns. Only because if it was working normal, it would be in the ball park. I have tried and tried to adjust it as you say but nothing happens. I can close it all the way, it should die or at least run bad, but like I said, nothing happens. I can drive it like that and it runs fine. I would argue that I have it jetted too high but it does this with any size jet from 112 to 138. It just don't have the performance with the smaller jets. First thing I thought when I first discovered this last year is that the carb was plugged. But this carb is as clean as brand new and I could spray carb cleaner through every port. It makes me crazy.

[Alleyoop]

But now you know, you closed the mixture screw all the way and it did not change a thing and the motor kept running. so what does that say is the problem:
1. The pilot jet is to big
2. The screw is to short and not blocking or doing anything to the fuel passage.
3. Fuel is being sucked out from some other place.

Now since you have taken the carb apart and checked it all out Did you maybe forget to put the Needle Guide in, that is the gold piece that should stick out about 1/8 into the Venturi so the needle does not come completely out and get stuck.
This piece:


You can get Mixture screw and the spring,washer and o-ring kit here:
www.cv-performance.com/ez-just-mixture-screw/

Alleyoop

[rsw1158]

I got it all back together and didn't leave anything out of the carb. I did notice that there was rubber residue in the air mix screw but I don't see where it was blocking anything. So I started it up and let it get warm and started to adjust the carb. Again, I could close the screw all the way and wait and nothing happens. Idles perfect. I backed it out 1 3/4 turns and waited and nothing changed. I ran the rpms up and it surges a little between 4500 and 5500 rpm. So I started backing the screw out more and after about 3 turns it started to slow down. So, I turned it back in a 1/4 turn at a time until I achieved top rpm at idle and was running smooth. Ran the rpms up and no longer have the little surge between 4500 and 5500. I took it for a test drive and it runs out perfect for now. I'm going to drive it like this for a while and see how it does. Still don't seem right about the mix screw. Maybe I will swap out then 38 pilot for a 34 since you mentioned it just to see if there is a change. I wouldn't think the 38 is too big.

Read more: thescooterprofessor.proboards.com/post/new/3651#ixzz30Us3SnFC

[Alleyoop]

thescooterprofessor.proboards.com/thread/3651/performance-problems-jonway-yy250t-cfmoto?page=1&scrollTo=29228

Your missing the tiny washer from a previois post and that is not good so like I said in the other forum I suggest you get kit.

And if your going to try a smaller jet get the #35.
Alleyoop

[rsw1158]

Sounds good. I'll do the suggested. Thanks.