Saving Old Seagulls

Hello from sunny France,
I have recently picked up a GF Seagull. I checked compression, spark, clean fuel, and after some effort it started and runs fine.
I didn't let it run for long since it had emptied my bucket so wasn't getting enough depth of water, but I'll try it on a boat to see.
I was surprised to find no choke, or tickler for the carb, and looking at all the information here and in the manuals I find no reference to this make of carb fitted to Seagulls.
It's a Zenith, 13L MX to be precise.
So I had a look on the web and found several diagrams and instructions for the carb. It doesn't have a choke or a tickler, but it does have a plunger you push to give a richer mixture for starting which gets pushed back up when you open the throttle in use.
Don't know how to stop it, but that must just need the idle to be lowered.
Here are the diagrams and photos if anyone is interested.
Oh yes, the motor is a GF, imported to France in 1975. The website says they were made from 1977. Odd.

Here are the diagrams.

GF models would have come with a Bing carb from the factory. But these carbs were not popular and often replaced on models I have seen, though mostly with the Villiers which was standard on other forty models at the time.

If having trouble with the Zenith, used Villiers carbs are widely available and still reliable after all these years.

Thanks Andrew,
I don't know how to get notification when there's a reply so missed yours, sorry.
Is there a particular model of Bing or Villiers carb to look for ?
This one runs very well but takes ages to start. I'm using an electric drill on the flywheel nut since pulling the rope just doesn't do it until it's warmed up.