2001 Yamaha F100 Carb Nozzle Position

[hribarj]

I have a 2001 Yamaha F100 with 4 Keihin carbs. I've been having problems with proper running. Last weekend I happened to meet two techs out test driving a boat. I told them about my problems and they said it was probably junk in the mid-range jet. Today, I tore the carbs down AGAIN and examined every nook, cranny and hole with a magnifying glass. All 4 carbs were clean enough to eat off.
When I was carefully putting them back together I noticed something that troubled me. I saw that the holes along the side of the MAIN nozzle are not symmetrical. That is, it might matter which direction the nozzle faces when seated. I looked in my service manual but it didn't mention anything about placing the MAIN nozzle with a specific orientation.
My question is, Does it matter? Could this be the cause of surging and rough running?
I haven't tested the mid-range jets on the water yet. I thought I'd check this out before I put the carbs back on.
Thanks for all the help.

 

[rodbolt]

Re: 2001 Yamaha F100 Carb Nozzle Position

doesnt matter and its simply an emulsion tube.
that carb has no midrange jetting just a main jet and a pilot fuel jet.
do you have the techmate vacum mate or similar manometer to set the carb shutters correctly ?
all those holes in the emulsion tube do is allow some air to start mixing with the main fuel stream to aid in fuel atomization.
just like almost every carb built in the past 90 years or so.