3D profile planes the size and weight of a Mojo 25 end up flying a LOT better with electric power instead of glow power. There is no glow engine available at any price to compete with electric power in that size range.
The problem is that if you use a glow engine that gives a Mojo 25 a good power to weight ratio for 3D, then the engine weight raises the wing loading to an unacceptable high level for 3D flying. If you use an engine light enough to keep the wing loading to an acceptable level, then it won't have enough power for 3D flying.
If you absolutely insist on using a glow engine in your plane, then look for an old Norvel bushing 25. It still won't be able to compete with an electric power system, but the Norvel 25 will give you the best overall performance with a glow engine.