Yamaha F2.5 carburettor settings

Hi All
I have the above engine, have cleaned the carb numerous times, checked the plug, compression and valve clearances etc but for the life of me can't get it to idle properly and it bogs down a little when I open the throttle.
It wasn't me - honest, but a previous owner has removed the plug and likely fiddled with the screw-air adjusting, does anyone know the default factory setting for this screw and if it had been fiddled with, could that cause the engine to run rich (which is what it's doing), failing that, any ideas anyone?

Yamaha offered F2.5's from 2003 thru 2020. Any idea what the model is?

Hi Boscoe, I don't have a serial number plate, all I have off the engine freeze plug is 1018888 and the carb sticker says its for an F2.5A "Family" It's pre 2016 as it has the older style water pump.

Look at the carburetor and the CDI assembly. Hopefully you will find 69M on either or both.

If so, 2.5 turns out from being lightly seated is the base setting. Then plus or minus one half turn.

If the carburetor has not been completely disassembled and cleaned in a heated ultrasonic cleaner, with all holes and passages confirmed to be free and clear, you may have been wasting your cleaning time. Also the float setting should be confirmed to be within specification as it will have an affect on the air/fuel ratio.

How are you getting to the position where you think that it is running rich? Most Yams are set to run on the too lean side IMO. Thanks to the EPA.

Awesome, Thank You, I have thoroughly stripped and ultrasonic cleaned the carb including removing the fuel air screw, float height is good. The engine will not start or idle unless the throttle is pretty much half open and it bogs down when I open the throttle, stalls if I close the throttle, taking the plug out after running and its pretty carbonned along with a slight smell of fuel when it's running leads me to think it's running rich, had another play last night and I'm not sure if there wasn't a small bit of leaf in the intake which would cause the same problem I guess but I am clutching at straws with this one.

I will check the 69M info tomorrow (When I can sneak into the garage )

Both have the 69M, runs a whole lot better after clearing out the air intake by back blowing it, still runs a little slow on idle and the air/fuel screw seems to have zero effect on the idle speed at all though.so I guess I'll strip and clean the carb again and again and again until I'm 100% sure it's nothing to do with that.

Happy Christmas everyone (but especially Boscoe)

Just an update, was getting on my nerves so bought a new carb, now runs just fine so there's something amiss in there that I'll have to get to the bottom of, runs fine now, a little smokey but I can live with that.....