8. On the single needle carburetors on Plonker models, the float is not adjustable.  If it leaks or breaks, replace it.

9. If the engine runs rich at all throttle settings, check the float as detailed above.  Carefully check the seating of the float needle and float metering jet, as fuel may enter the float after the needle closes.  Be sure the float is airtight so it does not contain fuel inside it.  These conditions cause fuel to spill over into the carburetor, flooding the engine.

10. If the engine runs lean at one or more throttle settings, refer to the appropriate section above for the proper adjustment.

11. If the engine runs rich at one or more throttle settings, refer to the appropriate section above for the proper adjustment. 

12. When adjusting more than one metering system in the carburetor, always start with the smallest throttle opening and finish with the largest.  This ensures a smooth blending of systems as the throttle is opened.  This precaution will prevent the necessity of changing the larger opening adjustments more than once.

Fine Tuning

1. After the rough tuning is complete, ride the machine 1/4 mile at 1/8 throttle opening.  Hold the throttle opening steady and turn off the ignition and immediately disengage the clutch.  Remove the spark plug and check it.

2. If the machine has no ignition switch, set the idle speed screw so the engine will not idle.  Ride at the throttle position and simultaneously pull the clutch and turn off the throttle.  Check the spark plug.
3. Do not use a compression release to stop the engine, as it will alter the carburetion and plug reading.

4. The spark plug insulator should be light brown.  If the color is very light or almost white, the mixture is too lean.  If the plug is dark or oily, the mixture is too rich. 

5. Refer to the appropriate section above to adjust the carburetor for that throttle opening. 

6. Repeat the test for 1/4, 1/2, 3/4 and full throttle openings.

7. When all adjustments are complete, repeat the tests at each throttle opening again, beginning with the smallest through the largest, to be sure each one blends with the next for fine tune.