In general, two stroke engines burning low nitro% prefer a hotter plug, while higher % and tuned pipe equiped engines will like a plug on the colder end of the scale. Most sport engines will like a plug in the hot to medium range, with the cold being prefered for car and boat racing.


You may want to start with a hot or med-hot plug with 5% fuel in your tower 75. If the engine runs hot, try a medium.