My method, drain all alcohol and blow out the pump and all the lines. I use Marvel mystery oil, pour some in the line going to the barrel vave and open the throttle and blow/force it thru the injection system, pour some into the pump and rotate it to make sure all parts are coated. I have found in the past that WD 40 drys out and it's also corrosive to the alum parts. A lot of the pump builders (aka DSR, etc) ship their pumps with Marvel Mystery oil in the pumps. Many yrs ago when i was running a blown alcohol alum BBC we used to after every race blow out the pumps and put Mineral Spirits thru the system. That was a weekly ritual, but that was over 20 yrs ago.
JMO
Zip.