O.S. has developed a long-awaited 2 stroke gasoline engine. The GT55 was expressly developed for hobby use to meet the many demands of O.S. fans and large gasoline engine users. The external appearance was designed after conventional O.S. glow engines to enhance the O.S. quality both inside and outside the engine. Please check the new O.S. blood line of engines at an airfield.
With the carburetor mounted in front you get the following advantages
a)Throttle linkage, needle adjustment and choke valve operation are easily made.
b)The carburetor is easily cooled which is better for heat migration.
c) the standoffs are much shorter or not needed, which enables more secure engine installation and results in less vibration of the engine.

The IC magnetic sensor consists of a magnet installed in the drive hub with the pick-up sensor mounted on the crankcase. This makes it easy to control ignition timing. It detects a stable position signal for starting and from idle to high speed.

O.S.’s precision machining is done on the cylinder liner to achieve accurate scavenging and exhaust timing. The piston is machined from low expansion and high durable aluminum alloy and the connecting rod is machined from extra super duralumin block.

Since a rotary shaft valve is employed, the valve is opened and closed at optimum timing. Also by eliminating an oil seal it greatly reduces rotation loss.
CDI which is strong against wet plug condition is employed. It keeps high voltage up to high RPM, which reduces misfiring. The idling current is very low. It also has a function to warn voltage drop of current source by intermittent running.
Dense and deep head fins as well as crankcase cooling fins allow better cooling which is vital with a gasoline engine that generates higher heat.


●Bore: 41.2mm(1.62in)


●Practical RPM: 1,500〜8,000r.p.m.

●Power Output::5.5ps/7,000r.p.m

.>............Igniter : 140g(4.94oz.)