I've been flying nitro planes since I can remember, but I'm now gettinmg into larger scale planes w/ gasoline engines... I've found some used ones;
1 is an 18 cc Poulan converted engine w/ a timing mechanism on it, 1 is a US 41 w/ a spring starter on it, 1 is a zenoah 23...all are used, all different...Now I am seemingly lost on a few things:

1). what is a proper voltage source for a gas engine?
2). Should each engine take a different voltage ?
3). Should this battery be different than the receiver battery?
4). Gas top oil ratio ?
5). Best priming/ starting procedures?
6). Are there any wiring diagrams out there for optimum set ups ?
&). Any other tips ?