The first video - sounds like it was running smoothly, but you had your foot on the throttle pedal keeping it revved up. Is that because the engine won't idle by itself?
The second video (attempting to start the motor) -- sounds like the choke is not closing all the way, which will make it very hard to start
One thing that's somewhat common and can cause it to not idle is if the Idle-cut solenoid is not working. It will run fine at 1500-2000 RPM but won't run below that speed. See our tech article (click
Anti-diesel valve) for troubleshooting
For the hard starting, you already have the air cleaner lid off. Pump the accelerator pedal one time then look down the carburetor throat. Is the choke flap 100% closed? If not, if it's open even a little bit, it will cause hard starting
good

if it's open this much it may not even start

The 210 is jetted quite precisely so doesn't use a lot of extra gasoline when starting. Other cars/older engines may start fine with choke a little open in warm weather -- but not the 210