Quick & Dirty Tuning Diagnosis

Here's a general guide to troubleshoot the most likely problem when your GY6 stumbles while riding.

When you notice a Stumble, Back off the throttle about 1/4 turn.

1. If the RPM's surge, you are running Lean

2. If it hesitates for a moment, then recovers, you are running Rich 

Based on Throttle Position, different adjustments need to be made:

1. Stumble as you first crack the throttle open = Adjust Air/Fuel Mixture

2. Stumble in the mid range = Adjust the Needle height

3. Stumbles at WOT = Re-Jet.