Installed an oil thermostat in my 912S today. Purged the engine per Rotax instructions, without preheating the oil or the thermostat,and it purged and started beautifully. My installation is an open pusher configuration and I have always had long warmup periods. Even at cruise its hard sometimes to keep the operating temps up to nominal levels. Don't know about cruise temps yet, but my warmup time has been cut almost in half.