1. Small Engine Carburetion Adjustments & Troubleshooting Ch 13 u Adjust air fuel ratio on 3 basic carburetor designs. u Perform altitude adjustments on 3 basic carburetor designs. u Troubleshoot an engine to determine if a carburetion problem exists. u Understand how the Pilot (idle) Circuit, Main (high speed) Circuit and Transition Circuit work and what effect they have on engine performance. u Adjust choke for proper operation u Troubleshoot carburetor related problems as they pertain to engine performance. Chapter Objectives Upon completion of this chapter you should be able to: Chapter Objectives - Upon completion of this chapter you should be able to:

2. Small Engine Carburetion Adjustments & Troubleshooting Ch 13

3. Small Engine Carburetion Adjustments & Troubleshooting Ch 13 Choke designs and adjustments

4. Small Engine Carburetion Adjustments & Troubleshooting Ch 13 Fuel inlet needle and float adjustment

5. Small Engine Carburetion Adjustments & Troubleshooting Ch 13 Fuel inlet needle and float adjustment Float too low: Engine will starve for gas Float too high: Carburetor will overflow Float level to carb. Body: Correct Adjustment

6. Small Engine Carburetion Adjustments & Troubleshooting Ch 13 Idle Speed Adjustment Turn the screw in to increase low idle and out to decrease low idle

7. Small Engine Carburetion Adjustments & Troubleshooting Ch 13 Air fuel mix adjustments Adjustable High Speed Fixed High Speed Non-Removable Fixed High Speed Removable

8. Small Engine Carburetion Adjustments & Troubleshooting Ch 13 Adjustable High Speed To adjust air fuel ratio for altitude changes, Turn the High Speed Needlevalve in to lean and out to richen the mixture.

9. Small Engine Carburetion Adjustments & Troubleshooting Ch 13 Fixed High Speed - Non-Removable To adjust air fuel ratio for altitude changes, remove the main jet air bleed restriction(s)

10. Small Engine Carburetion Adjustments & Troubleshooting Ch 13 Fixed High Speed Removable To adjust air fuel ratio for altitude changes, remove the jet and replace it with proper jet according to altitude engine will be run at.