Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Bonjour Raphael,

Not quite,
1. First we set the main jet, this is the silver one by the fuel inlet pipe (ignore the other jet for a minute).  Open the throttle fully and adjust this jet until the engine runs at full throttle. 
2. Then reduce the throttle until the engine starts to run badly, this is the time to gradually adjust the slow speed needle (the gold one in the centre of the throttle arm) until the engine runs nicely.
3. Repeat step 2 until you can get right down to a fast idle speed.

I have a feeling this engine will overspeed at full throttle with no load,  if this is true then keep adjusting period very short, we only want to find a baseline setting for now.

For this type of carb in an RC engine the main jet setting is critical to provide full power and keep the engine rich enough not to overheat, but with this little engine we only need a basic setting of the main jet for now so the slow speed needle can do its job.

I hope this helps
Ade