Rotax 912UL difficult starts sometimes.

Good morning Roger and thank you for your coments Sir.

My Electronic Modules are mounted verticle and have lots of stuff around them. 
I placed a frozen bottle of water (that's all I had with me this am) as close as I could to the Modules, then wrapped with a bunch of rags all around, to contain the coolness. Waited 30 minutes and tried again. Engine would not start. I have included a photo. 

Gino

Just because you start it during low temps does not "rule out" vapor lock, which may have happened when things were hot after your last shutdown.  

An electric pump with a return line could purge any vapor before you try to start – if you are using just the mechanical pump, it may need to pump for a while (during starting) before it gets purged.

Gino, don't rule out what Roger said in regards to the ignition modules, get some ice and make them COLD. This is a fuel or ignition issue.

The water4 bottle is not cold enough. You'll need ice around them.

Tyler

Thank you for the suggestion

My problem is intermitten. This afternoon I had no start again and I was able to verifie no ignition spark. I am sending the Electronic modules to Vernon BC Canada "Rotech Motor Ltd" They are a top notch service and repair Shop. 

All the best

Gino