Hi Lock-Os,
I tried several time until I'm able to do the startup pretty well. SO what I learned ? The first thing I learned is ;
The I-16 is really, really, really whimsical.
One thing seem important, the primer, 5 primer is enought. More, you risk drowning the carburator, less you do not have enought fuel. And the second important thing, maybe will show you idiot, follow the startup checklist letter by letter.
And to boost you a little bit, I never suceed on the first try, I must always try to start the engine two or three times. So don't give up.
Fly safe.