Homelite ST155 trimmer 25cc cold start

Light string trimmer with 25cc displacement 2-cycle engine.
Made by Homelite in late 1980s or maybe early 1990s
This video shows how engine starts when cold. Primer bulb is pressed a few times to bring fuel into carb. Carb choke plate is set, then pull on the rope.
The second pull almost starts, then the choke is placed in 1/2 position.
Usually the next pull of rope will start, but in this case another pull was needed. The engine then runs with 1/2 choke for a short time, up to a minute until the choke is finally set to RUN position. That means choke plate is fully open. Engine runs at full speed with trigger pulled in. Release trigger and the engine speed drops to idle. This engine had been stored for years, but the day before I put fresh fuel mix in the tank and engine started easily. The fuel mix is ordinary gasoline with 2-stroke oil added in ratio of 32:1 by volume.
For example with 32 ounces (1 quart) gas, add 1 ounce of oil and mix.
Or add 4 ounces oil to one gallon of gasoline. Engines of this era were often designed for 32 to 1 mix. Now it's mostly 50 to 1 (or 40:1) with the exact amount based on the brand or manufacture specified in operators manual.