Engine Run - MVVS G7 - Part 2

I testing this 1970s Czech-made MVVS G7 2.5cc glow engine a few years ago and found that it was in need of some refinement. Here it is after the first few improvements - a smaller venturi to allow it to run on a suction fuel feed system, and the head clearance set to a more effective level. Fuel is 10% nitromethane, 20% castor oil and 70% methanol. O'Donnell Sport medium glow plug. The model at the end is my Perky vintage speed model. Power estimates are derived from APC propeller data.