I use Futaba S3004 or even S3001 for all my servo applications. No problems yet. It doesn't require the crispness or return to center abilites of a digital. Carburators aren't that precise as to justify one (IMHO). It is the one place to save $. Just be sure to keep it well back of the engine, 10" or more, and connected to the throttle arm with a non-metal linkage like a nylon Gold-n-Rod, especially with EI.