Here's what I've done:
1. Cut out more area inside the nacelles so I could get at least some foam around the tank. I did both outboard nacelles the same.
2. No crud in the needle valve or lines.
3. I have always filtered the fuel before it goes in the plane.
4. All four engines (O.S. .25FX) have/had the same fuel, don't think that is a problem. I run 10%/16% oil Wildcat.
5. I am going to switch, at least for now, from the Graupner 10 x 6 3 blade back to MS 9 x 5 two blade props like I'm running on the C-130. When I was running up the throttles, I noticed a slight vibation of the prop nut when going through a certain rpm range, but all 4 engines were doing this-strange.
6. I also checked the klunk, fuel lines, etc for wear and tear or any signs of leakage.
I guess we'll see on the next outing what happens. That will be a couple weeks away, heading west next week for a bit.
Thanks for the suggestions,
Randy