* 2 cylinder engine * fuel /oil mix ratio 50:1 using 87 octane fuel and TCW-3 two cycle oil * Recommended sparkplugs are Champion L78-V surface gap for sustained high speed operation or Champion QL77JC4 gapped at .030". * WOT(wide open throttle) operating range is 5000-5500 RPM.Best to prop it to be capable of 5500.