On my 2001 Yamaha F40B, I am putting together my carbs after a complete overhaul and there is something weird on the carburettor dashpot : there are a nylon washer and two O-rings along the axle that look out of place.
The standard way of adjusting fuel mix is to rev up the engine and let it fall back to idle. If it takes too long to fall back, the fuel mix is too lean. If it falls sharply below idle, it's too rich.
I'm concerned that the dashpot might be affecting this reading since it slows down the engine returning to idle. Should I disconnect it before adjusting the fuel mix?
Do you have a way to balance the carbs? First do that then dial the mixture in. The dash pot may need to be disconnected to do so. Manual should state as such.
Mixture is also chosen by how it idles and snaps off idle. I gotta say I have never heard of anyone setting mixture by exacting how it returns to idle, but more by if it stumbles when returning to idle, or if it idles cleanly after a blip of the throttle. All of this also needs to be checked in gear and out of gear. Of course how it restarts is very important too.
The workshop manual doesn't say much about adjusting the fuel mixture. I found it quite hard to adjust the mixture on the basis of the tachometer alone.
