This may not help anyone but was watching tear down video an heard Tony speak of water collects on internal parts. From my experience in my racing days the fuel storage plays a big part in that also. We would was using methanol as fuel . I noticed that after about 2/3's of drum both EGT readings would start to increase 100 150 degrees an more moisture would accumulate in valve cover.. the water temp would start to rise too, classic signs of leaning out would have to fatin' up carb..fought that for a couple seasons. Don't know why but I decided to put nitrogen blanket on fuel stored in drum.what I done was put mounted nitrogen bottle in trailer put regulator/ flow meter on it ...evertime I got fuel out I purged drum with nitrogen ,think about it you replacing liquid with atmosphere..once started doing stoped the EGT rise was eliminated thought out entire drum..it didn't eliminate the condensation problem but helped a lot..to eliminate that after each run put shop vac in valve cover for a few minutes an just about eliminated the moisture problem. Can't do that on these motors but you might could EXHALE in your fuel container to disperse oxygen an that replaced fuel...just a thought