If you are not so satisfied with the K144XV transverter module installed in your Elecraft K3 transceiver then you should read it...
Thanks to Steve, DH1DM you can make "must have" modification which could solve your issues or it can help you at least...
After re-tuning has been completed these modifications result in an increased TX stability and no oscillations can be observed anymore at any power/frequency.
Component alignment has also been found less critical after modification. Output power has been measured at 9.5W.
73 - Petr, OK1RP