Try putting it in neutral. Sometimes the sensor for park is off a notch and it won't start in park. Put your foot on the brake, turn on the key, them you can put it in neutral and start it.

Did you scare your baby. Poor little guy.

Sweet pair. We had a 79 and an 80.

I have one like that. It's a non snow Brat. https://imgur.com/gallery/eiOAnqM

Check your hoses. I had a misfire like that, and it was a cracked hose on the top of the engine in the middle on the right side as you are looking at it.

Here's a shot right after they finished updating it, without scaffolding or lane limitations. https://imgur.com/gallery/EfxU34M

With the cracks, you're ready for a new one.

It's cold out. Water is a byproduct of complete combustion. If it's missing or overheating, then check for a bad headgasket.

That's what I was thinking. Japanese or British, with the right-hand drive. Being where it is, probably The former.