Somehow I missed post #11 before. Sorry about that. The engine you are using is fairly small, so you will need to keep things light. Why not just use exhaust pressure as is usually done for your fuel pressure? There are also small, engine driven pumps (Perry pumps), but maybe not for that small of an engine. I would think that a constant pressure pump independent of the engine would lead to difficult starting (you would have to start with pump off) and additional weight for the batteries to run it.

John

 

The batteries onboard are already incredibly high capacity (2100mAh) for what they are used for, they last half a year with out needing charge so I think the power situation is sorted. This is a college project so I wanted to make a project that could include both mechanical and electronic.

And those perry pumps require you to drill a hole in the rear of the crank case to get the crank case pressure, not quite sure why this does not stop the fuel flow because it is that pressure that pushes the fuel into the cylinder to begin with.

Anyway, here is what I was thinking for the encoder.

 

I am checking the voltage over the ir leds in a roller wheel mouse but it only says 0.2 volts :s