150cc gy6 motor: unresponsive throttle after deceleration

[MMRacing]

After idling, when I attempt to accelerate, the engine does not respond any throttle input. This only happens after deceleration. However, if I keep the engine speed up while slowing down or stopping (gas and brake at the same time), the this issue can be mitigated. If I let it engine speed fall to idle, throttle input is useless again. Eventually (10sec - 10min later), the engine seems to “catch up” and begins to take throttle input and runs until I come to Idle again.

This is not a linkage issue, as I have attempted manual input at the carb as well as the pedal. I have disassembled and cleaned the carb to look for issues, but everything appears to be in working condition. Also, the carb is being filled with fuel without issue (floater is working properly).

I am at a loss and would really appreciate any help I can get.

Go-Kart Model: Maxxam 150 2R
(150cc gy6 motor)

 

[Brianator]

Carb has a mixture screw ya? Screw it in until it's lightly seated taking count of how many turns, 1.5 turns out is usually good starting point. Think of it like a clock face and make 1hr adjustments allowing 20 seconds for the new setting to take affect, test after each time to see if it's improving or getting worse and that should lead you in the right direction!

 

[MMRacing]

Carb has a mixture screw ya? Screw it in until it's lightly seated taking count of how many turns, 1.5 turns out is usually good starting point. Think of it like a clock face and make 1hr adjustments allowing 20 seconds for the new setting to take affect, test after each time to see if it's improving or getting worse and that should lead you in the right direction!

@Brianator,

I appreciate that advice, but I’ve already tweaked the A/F mixture screw. Even when it was running rich, it was still happening.

 

[Brianator]

What setting is the jet needle at? Also check it to make sure it's not bent, that can throw things off alot!

 

[MMRacing]

@Brianator I didn’t know that there were settings for the jets. Currently, they are fully tightened, as per the factory setting. I will look into possible configurations because I do not know how to adjust the jets without leaving them loosely in place.

 

[Brianator]

The (jet) needle is the only adjustable one, it controls the midrange. If you're able to look inside the carb mouth, have someone open the throttle and you'll see the needle right away. To check/adjust the setting you must remove the throttle slide. Quick question though, is this machine new to you or did this just start happening?

 

[MMRacing]

@Brianator I’ve had this go-kart for 13 years and never had an issue until I moved. After the move, we had issues with the carb and took it to a local shop. He “tuned the carb”. That was about 2 years ago. Since then, this idling problem began, but it has slowly gotten worse and worse. I appreciate your help. I will try to figure out how to adjust the needle.

 

[Brianator]

You might want to tear the carb apart and clean it thoroughly then if it's been sitting for 2 years, fuel could be dried up inside and is partially blocking the port(s) or jet(s).

 

[Mr_mcrib212]

If its that much of a pain just get a new carb if nothing else works

 

[Brianator]

If its that much of a pain just get a new carb if nothing else works

Hey don't you have a death trap to build!? Quit wasting time!

 

[Budget GoKart]

There might be a vacuum leak somewhere i had a four wheeler that did that. I put a bolt in the vacuum hose and it ran great.