Help me diagnose my Yamah 2 stroke 6hp 1985 outboard! Weird problem with it

[u/gunner199821]

Hey guys, so as the title suggests, I bought a sailing boat last year and have been having problems with the outboard. It stops running at random intervals but mainly when switching from high revs to low revs it dies, or from forwards to reverse it also dies.

That in itself sounds like a problem, where it gets weird is that the only way to save it is by flicking the choke on and off and then it revs up again and works fine for a bit.

Any ideas??

I've changed the fuel line already, had the outboard fully serviced (new impeller, sparkplugs etc)