RE: Coleman Fuel in ZDZ 100 NG ??
Burns smoothly? The octane rating is THE measurement of a fuel's resistance to detonation. Coleman fuel is low octane (around 70), so it has poor resistance to detonation.
I've only run premium in my ZDZ-80, although some friends run 87 octane (regular unleaded) in theirs. The distributor recommends premium because of the high compression ratio. Other things that contribute to detonation are high loads (full throttle and large diameter/pitch props), hot weather, poor cooling air flow in the cowl, too much ignition advance, too hot a plug heat range, and lean fuel-air ratio.
If you must run a low octane fuel, you may have to work on those other things that contribute to detonation.