The OS MAX 91HZ is a high performance engine expressly designed for 90 size RC model helicopters. It performs perfectly from stable hovering to dynamic aerobatic maneuver, which is required for F3C competition.
The new 61B carburetor has three adjustable controls which enables independent adjustment at idling, hovering and high speed. A needle control arm is supplied with engine as standard. The needle can be tuned by the transmitter in flight or with a fully enclosed engine.