I am having trouble with my DL 50 in a Yak 54, and would appreciate any suggestions.
The top end is set to peak RPM, and the low end transitions to high speed immediately when the throttle is advanced.
The problem is with the mid range burbling, and hard starts. I flip it 30 times full choke sometimes and nothing. I have pulled the plug after many flips with full choke, and the plug isn't wet. Warm restarts usually require choke. The electrode is a medium tan color.
On my last flying session, I had 2 dead sticks after a maneuver. Up to now I haven't had a dead stick in 7 gallons of fuel.
The carburetor is vented into the fuselage. The cowl is baffled to only allow air to go directly through the cooling fins, and the exit is several times larger than the intake. I put a large louver at the front of the exit hole to create negative air pressure in the cowl, to promote a good air flow of out of the cowl. I also installed one of the black plastic venturi on the carburetor.
The timing has been checked, and is right on.
I am running Viton tubing, and two fuel filters before the tank. All tubing connections are zip tied.
I run the Xoar 22 X 8, or Vess 22 X A or B for the prop, and use regular gas with Penzoil air cooled.

Thanks in advance,
Greg