ORIGINAL: striderjg
... and you don't need a glow plug as they have onboard ignition systems.
-John
On the other hand you need an ignition system and a spark plug. The ignition system needs to be shielded in order to avoid RF-intereference.
I would say that somewhere between 1.2 and 1.8 cu.in. the advantages of gas engines will outweigh the advantages of glow engines.
For small capacity engines (say below 1.2 cu.in.) there is not much to gain from going gas.
/Red B.