Tuning Guide Continued
Tuning Guide Continued
NOTE: Never over tighten the tuning needles when adjusting. This will cause
damage and poor tuning ability.
Spark Plug Tuning
There are a few performance gains from understanding and tuning the spark plug of a gasoline
engine. The basic areas of interest are the Air Gap and Color of the spark plug used.
Spark Plug Air Gap
- the distance between the outer electrode and inner electrode.
The main issues with spark plug gaps are:
• narrow-gap risk: spark might be too weak/small to ignite fuel
• narrow-gap benefit: plug always fires on each cycle
• wide-gap risk: plug might not fire, or miss at high speeds
• wide-gap benefit: spark is strong for a clean burn
A properly gapped plug will be wide enough to burn hot, but not so wide that it skips or misses at high
speeds, causing that cylinder to drag, or the engine to begin to rattle.
Standard Spark Plug Gap - 0.6-0.7mm / 0.023-0.0275in
Reading the Color of the Spark Plug
•Normal Operating Color - exterior electrode has a very light tan color, resembles ash, the interior
electrode has a clean brown color, no deposits on any surfaces.
• Dry or Wet Fouling - the overall appearance of the plug is black and sooty or very wet with an oily
appearance.
• Over Heating - The plug end will appear glazed especially around the ceramic insulator
Replace wet, fouled, or damaged spark plugs and try to determine the cause of the fouling. Its ok to
clean a spark plug if a replacement is not available but for optimum performance the fouled plug
should be replaced. The color of the plug will indicate the operating condition of the engine internally.
Adjusting the carburetor and using the correct fuel mixture will usually correct the problem.
Gasoline to Oil Ratios
The two stroke engine relies on a delicate mixture of oil mixed in with the gasoline in order to perform
at maximum performance levels. Since the oil which lubricates the engine is mixed in with the fuel it is
possible to cause severe engine damage and total failure if the mixture is incorrect. Please follow
these guidelines to ensure proper performance and good engine life.
Fuel Ratios
How to read the ratio of gasoline to oil:
The ratio above is related to 1 US Gallon of gasoline. The more rich the ratio the closer the relation-
ship of gasoline to oil is 1 part to 1 part (1:1). The number on the left is the amount of gasoline used.
The number on the right is the amount of oil. The smaller the gasoline number, the more rich the
mixture will be because there is more oil in relation to gasoline.
Use high performance 2 Cycle Premix Oils that contain Castor Oil and Synthetic Lubricants commonly
found at Motorcycle Dealerships, Go-Karting suppliers, Gardening and Power Tool Supply stores. Use
a proper oil ratio measuring cup or container.
20:1
Initial running - 1hr
25:1
3hrs
30:1
Standard operation
32:1
Only recommended for experienced tuners
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Summary of Contents for VEN-1827
Page 10: ...Notes Notes...
