Saving Old Seagulls

Doing a bit of thinking about these carbs, & the reason why mine was very rich at idle. Who had a moped when they were younger?
You had to follow the revs with the twistgrip. At slow speeds, wind the throttle fully open, and you actually slowed down.

So, the potential airflow depends on the revs, the engine is an airpump. Vacuum depends on how closed the throttle slide is to this potential airflow. Fuel depends on vacuum versus how much needle is stuffed into the jet. Load on the engine slows down the airpump effect. This drops the vacuum, so drops the fuel, so leans the mix.

So, running the engine with no load, out of water, it revs faster, sucks harder, gets more fuel and so goes too rich & four strokes......
........Er possibly.

Does a colourtune sparkplug work on two stroke, or does the oil change the flame colour?

(Argh! Why does this site have an american spellchecker)

Did bing make a CV carb for 14mm chokes? It would remove a lot of guesswork.
What was the smallest SU carb? that would be fun.

Just wondering for fun.

A colourtune spark plug will work on any engine 2 or 4 stroke, just make sure it has the correct thread adapter before you use it. I havn't used one in a 2 stroke before although i wouldn't think the oil would give much of a change in what you see in the sight glass!

Why not just keep things much more simple and "read" the plug!


Jon