I bet the problem is that the instructions that came with the incubator were originally in Chinese and translated to French.
I ran into the same with STC controllers from China that had worthless English instructions from a poor translation.
That's what I end up doing sometimes.
So true. I...
Vous ne parlez pas français ?
In what part of the country are you located?
The following is for chicken eggs but since they require the same temperature, most of the information applies.
http://www.brinsea.com/Articles/Advice/PowerOff.aspx
There is some great information in the following...
The trick with many incubators is to let them sit for quite a while and then, if you have to tweak it, make very minute adjustments and wait again.
What kind of thermometer did you add?
Most are notoriously inaccurate.
I found 2 that I really trust...
Have you done step 8 in the instructions, or are you hoping the digital reading is accurate?
8. Place another thermometer inside the unit to compare temperature reading with unit digital reading display.
Does the incubator have a fan?
37.7 is plenty warm if a still air and measuring at the top of the egg.
Too high if it has a fan. It should be 37.5 the first 25 days and drop to 37 for the remainder.
http://www.metzerfarms.com/IncubatingAndHatching.cfm