OK, in the name of science here's what you do. Switch back to Klotz to see if the problem returns - no other changes. If the problem comes back after 75 flights without problems with another brand of oil, then you are 100% certain that there is something wrong with the Klotz oil. At that point I would save the rest of the oil in the Klotz bottle, contact Klotz and ship it back to them.

I still don't understand how any goo could get past your clunk filter. If something is precipitating out of the fuel mix inside the carb passages, you should be able to see it when you take the carb apart. Also if you mix up some of the Klotz and gas and put it in a small glass jar, you can let it sit for a few weeks to see if anything settles out.

My buddy HT has a case of Klotz that he is planning to run through his ZDZ motors after break-in. I'll let you know if there is any trouble with the engines quitting.

If you are looking for another synthetic, I have been using Redline Allsport at 50:1 for hundreds of flights with a 3W-100 and about 60 flights in a ZDZ-80.....not a hiccup and the needles never get adjusted.