Russia AC-5M Engine Problem

Does it have a mixture control? If so check function.
UH

No mixture control. The Til;otson HR-194A carb is a automatic adjustment diaphragm type. There's a fuel shutoff valve but it's located on the fuel tank and there's probably 2m of fuel tubing between that valve and the carb.

I had a funny moment when I last used the shutoff. I had run the tank almost dry and replaced the 100LL with some ethanol-free gas I'd purchased. After closing the valve, and stopping the engine, I got out and manually reopened it from underneath the tank. The fuel in the clear fuel filter instantly snapped from blue to orange.

I'd never seen orange gas before and so I started furiously searching online to see what I had broken. Turns out it was just the color which arose from mixing the ethanol-free's dye and the 2-cycle oil. Because of the shear amount of suction-- which had effectively collapsed all the fuel tubing-- the orange gas mixture was pulled all the way from the tank to the carb in a heartbeat.

Derp.