912 UL jetting

Have you been idling before checking plugs? It can be normal to get dry black spot on plugs in idle rpms. What are the plugs gapped at? That burns off at higher cruise rpms. 

My plugs are gapped at .031. The spark plugs were checked after a run up to 4000 RPM to check mag drop.

Reduce the plug gap to .025 gap. Unscrew each plug wire to the plug rubber boot and trim each wire back 3/8", apply a dab of dielectric grease to the end of each plug wire and screw them back on until they are fully seated. Now repeat your test. 

Mag drop test time isn't long enough. It needs to run at those higher rpms much longer.

Thank you. 
I am assuming then that my jetting is ok for my elevation? I will reduce gap and reply with results.

thanks

Use your EGT's to help for carb adjustment. This should be more aimed at high rpm settings like cruise and climb. Make sure the mixture screw on the bottom of the carb is adjusted properly.  Make sure carbs are synced.

I never check the plug real burn at idle circuit rpms.