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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

- 5 -

Summary of Contents for VEN-1827

Page 1: ...Marine Engine but you have also joined the Venom Team and it s world class product line and customer service Please fully read and understand this instruction manual BEFORE operating this product Not...

Page 2: ...ot use gasoline with any alcohol or ethanol added Use a high performance 2 Stroke Premix Engine Oil Mix Ratio 20 25 parts Oil to 1 part Gas 20 25 1 for break in period 30 1 standard mixture The carbur...

Page 3: ...ngine in place 7 Repeat as necessary until the engine either starts or shows signs of starting 8 You may adjust the low speed needle either open or close to help the engine start but only in small inc...

Page 4: ...full power If not readjust the High Speed Needle until you hear a smooth crisp exhaust note This will be the maximum performance setting for that particular day and will require fine tuning depending...

Page 5: ...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 th...

Page 6: ...ce of an optimal propeller Some experimentation will be required to obtain the best performance possible Propeller Diameter range 65 75mm Pitch Ratio range 1 4 1 9mm Pro Tuner Tip Experiment with mult...

Page 7: ...g Replace Cylinder Piston Set 2 Gas Leakage from Cylinder Crank Case Gasket Apply Liquid Gasket Reassemble 1 Choked Breather Air Hole Clean Breather 2 Clogged Carburetor Clean Carburetor 3 Fuel Lines...

Page 8: ...stomer Service at 800 705 0620 or customerservice venom group com Copyright 2008 by Venom WARNING This product is not a toy It is not recommended for children under 14 years Minors should be accompani...

Page 9: ...31 Cylinder Gasket KWA VEN 1832 26cc Piston KWA VEN 1833 Piston Ring VEN 1834 Piston Pin VEN 1835 Snap Ring VEN 1836 Positioning Washer VEN 1837 Need Bearing VEN 1838 Intake Gasket VEN 1839 Bolt M5 25...

Page 10: ...Notes Notes...

Page 11: ...vice 800 705 0620 customerservice venom group com www venom group com Venom Group International United States of America 600 West Buckles Road Hayden ID 83835 Australia P O Box 7325 Alexandria NSW 201...

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