Matt,

If the engine operates over a reasonably broad rpm range, I suggest the microcontroller will have adjustable timing and duration for direct or port fuel injection, and adjustable timing and duration for spark. I presume measurement of exhaust gas temperature and free exhaust oxygen will be necessary to peak the engine performance over the intended range of rpm and hp. The control program will likely need to make use of various fuel/air maps that have been converted to lookup tables. A start fuel limiter will be desirable to reduce engine start emissions (and smoke). Are there other engine control related servo loops that would be appropriate for the engine controller to close, such as the choke iris, or butterfly valve (for a carbureted engine)?

Good Luck - Bruce