Glow plug ignition makes the ggt15 a unique 15cc gasoline engine ◠its performance is the icing on the cake! one of the most important benefits of using a glow driver is that it reduces the engine's overall weight by eliminating the ignition module. Additional features found on this exceptional engine include specialized shell-type roller bearings and a 61h carburetor with pd-08 pump system. It â’s the ideal power plant for larger,. 61-. 91 class models.