I’m hoping someone can help me resolve a rather frustrating issue(s) I’m having with my DA-50 (newest version). A little background.. I have about 10 gallons through the engine. For break-in, I ran 5-6 gallons of Lawn Boy Ashless at 32:1 with an NX 22x8. Throughout the break-in, I left it a little burbly rich on the bottom end. The engine performed flawlessly with incredible power but would almost deadstick intermittently on downlines and would always deadstick in inverted harriers/elevators and inverted flatspins. I attributed this to being possible too rich and loading up. Now that I’ve got ~10 gallons through the engine the problem still exists..

Tuned for solid idle, snappy transition and peak RPM the engine at acts like it is very rich on the bottom end. It will burble, sputter and cough at anything under half throttle. I could deal with the sputtering as the engine runs awesome otherwise. Unfortunately, tuned like this, it will also quickly load up and die in a low-throttle inverted situation like an inverted harrier/elevator. If I lean the low end out enough to take away almost all of the burbling and sputtering, the engine will not idle reliably. The idle RPM will slow decrease until it dies. If I let it idle for several seconds (if it hasn’t already died) and increase the throttle it will either not respond and die or it will cough sputter and then slowly increase in RPM.

I’ve found that the engine richens significantly in flight. If I tune the low end so it will not idle and/or transition well on the ground it seems to be better in flight (in fact, it’s almost too rich, still). The is annoying because I have to start her up and keep the goosing the throttle to keep it running before taking off.. I soldered a brass tube over the carb vent and ran a piece of fuel tubing into the engine box but it didn’t seem to make much difference. I’ve tried every single needle combination possible with no real productivity. I’ve tried both the stock muffler and a Slimline Pitts. I’ve tried different octane gas, different mixtures of oil, etc.. The engine has incredible power (turns an NX 22x8 at 7440RPM rich and a PT carbon 23x8 at 6900) but I’m limited to what I can do because I’m afraid of a catastrophic deadstick. Low, slow, inverted and deadstick is not a good combo!

Sorry for the long-winded post but I’m overly frustrated at this point.. Any assistance would be greatly appreciated.

Thanks,
Abram