I'm running an older hobbyco deluxe 12v starter with a Zippy, 3s, 2650 Lipo.
Worked fine till the weather got colder, now it wont turn over my .40 - .60 glow engines

would putting 2 batteries in series burn out the starter? ( 22.2 volts in a 12 volt starter )
would it give the starter more kick?

Also, can the "brushes" in the starter be replaced?
I have another starter that stopped working and when I took it apart the brushes fell out, the wires connecting the( worn ) brushes broke.

Thanks

Steve