912ULS Vs. 912iS Warm Up Time

Not sure.....

However the IS injection system runs the engine "leaner" an IS system has closer to correct fuel ratio all throughout the range. Leaner equels hotter.

It may also be deliberate, you can in a computer system look at startup and warmup parameters and lean off even more to deliberately warm up..I do not know if Rotax has done this.

Be sure you are comparing Apples...
The 912is installations may be more "Sophisticated."

My 912is has both an Oil Thermostat and a Coolant Thermostat.
It warms up quickly due to the fact that both coolant systems are essentially disabled by the thermostats until the temperature reaches 185°F.

If the ULS engine are installed with Open Loop Cooling,  You will see slow warmups and owners taping over the radiators during cold weather in order to keep the engine from being Over-Cooled.

Contrary to common belief, the thermostat is Not there to keep the engine Cool, it is there to keep the engine HOT!

Thank you for your quick responses.  I will share your information with the RV-12 VAF group.

I see you live in North Ridgeville, OH.  I'm in Hinckley and keep my RV-12 at Mole (1OA2).  

Pleasure meeting you...

Bill Hertzel wrote:

Be sure you are comparing Apples...
The 912is installations may be more "Sophisticated."

My 912is has both an Oil Thermostat and a Coolant Thermostat.
It warms up quickly due to the fact that both coolant systems are essentially disabled by the thermostats until the temperature reaches 185°F.

If the ULS engine are installed with Open Loop Cooling,  You will see slow warmups and owners taping over the radiators during cold weather in order to keep the engine from being Over-Cooled.

Contrary to common belief, the thermostat is Not there to keep the engine Cool, it is there to keep the engine HOT!

What model oil and coolant thermostats do you use?

Many use Permacool.