Carburator Fine-Tuning

[metricyamaha]

This engine is an '05 50HP TLR two-stroke.

I just need to verify: which way should I turn the air-mixture adjustment screws?

Which way is more lean, and which way is more rich?

Different sources all say different things.

Is there any trick to balance the mixture across all three carborators? I see no way to hook up a vacuum guage in order to check...

Thank you,
Metric

[WarEagle]

pilot screw???

If you are talking about the pilot screw. Located top rear and left as you look at the front of the engine. Best to find a service manual for the settings. But I can tell you that out is richer. They "meter" the amount of fuel (not air) from the low speed/idle jets to the idle port at the top of the carb throat. Just in front to the butterfly's. Half way between the butterfly's and the carb throat opening. I know this cause your carbs are the spitting image to mine on my 96 60hp. And I just got done rebuilding them no thanks to ethanol.
If you dont mind me asking, why are you adjusting them? The spring tensioner behind them should be keeping them from moving on their own.

[metricyamaha]

Thank you for answering my main question about the pilot screws... It was exactly what I was looking for.

I removed the screws in order to clean the carbs out. I remember that they weren't set equally from factory across all three carborators, but I forgot to write down the number of turns.

Still having a problem with shaky idle and low RPMs. I was under the impression that the screw adjusted the air and not the fuel, that was driving me nuts for a while.